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EIGHTEENALIENTAXAFROMNORTHEASTERN MINNESOTA:FIRSTCOLLECTIONSFORTHESTATE, REGION,ORCONTINENT
David J. Schimpf1and DeborahL. Pomroy Olga Lakela Herbarium Department of Biology University of Minnesota Duluth, Minnesota 55812-3004
Allium cepa L. × Allium fistulosum L. Liliaceae (orAlliaceae) walking onion
Significance of the Report. First report of this cultigen from outside of cultivation in the Great Lakes region.
Previous Knowledge. walking onion, also known as Egyptian onion, top onion, ortree onion,isanherbaceous perennialderived byhorticultural crossing of the parent species, onion and bunching onion (Maass 1997; Kim et al. 2003), respectively, which are themselves known only in, or escaped from, cultivation (Stearn1980).Thename Allium ×proliferum hasbeenusedfrequently,butitsacceptance is unresolved (The Plant List 2013). The plants produce small bulbs in theinflorescence,andthesewinter-hardybulbsmaybe plantedinautumn(Jones andMann1963)or spring togrow intoscallions. The bulbs may alsobe pickled. Theplantsusuallydonotdevelopseedsorlargebasalbulbs. Ifnotharvested,the growing mass of bulbs tends to bend the stem to a reclined position, whereupon someofthebulbsmayrootandestablish,enablingthecloneto “walk” acrossthe ground. Allium cepa × A. fistulosum was introduced into North America from Eurasia for culinary use.Although this hybrid was reported from outside of cultivation in Missouri and some New England states by Kartesz (2015), it was not included in the Flora of North America treatment by McNeal and Jacobsen (2002).
Discussion. Allium cepa × A. fistulosum was found growing in sand between a residential yard and the Lake Superior beach in Duluth, Minnesota, on public landwheregarden residueshadbeendumped. Theplants werein full sunamidst a dense stand of Ammophila breviligulata, American beachgrass, in a well- drained topographic depression. There were two live stems, one leaning and one reclining, at the time of collection. These bore multiple bulbs, and a few other live bulbs were detached on the ground. No leaves were seen. The impression is that the taxon is persisting here but not spreading to a meaningful degree. How
1Author for correspondence (firstname.lastname@example.org)
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long it has persisted is not known; the dump appears to have been there for several years, as judged by its very weathered pile of branches. Four live stems of Allium cepa × A. fistulosum were found there inAugust 2016.
Diagnostic Characters. The hollow stems were up to 1.1 m long and 3.5 cm in diameter. They bore bulbs at the top that were up to 2.5 cm in diameter. This combination of character states will exclude other members of the genus.
Specimen Citation. Minnesota. St. Louis Co.: Duluth, Minnesota Point, Nw¼ of Nw¼ Sec.12, T49N R14w, August 24, 2014, Schimpf 795 (DUL, MIN).
Allium sativum L. Liliaceae (orAlliaceae) Garlic
Significance of the Report. First report of this cultigen from outside of cultivation in Minnesota.
Previous Knowledge. Allium sativum is an herbaceous perennial derived through perhaps millenia of horticultural selection from an undeterminedAsian wild progenitor (Cavagnaro and Galmarini 2007). It is propagated asexually for culinary or medicinal use of the compound bulbs and sometimes the peduncles (“scapes”). The inflorescence produces asexual bulbils (topsets), with few or no flowers or seeds (McNeal and Jacobsen 2002). The bulbils enable local spread, as could separation of the bulbels (cloves) from the compound basal bulb. The species is documented as growing outside of cultivation rather sparingly in the western Great Lakes region (Kartesz 2015). Several states farther south designateitasa noxious weed (Kartesz2015),presumablybecauseingestionbydairy animals makes their milk unfit for human consumption.
Discussion. Allium sativum was found growing on the street-side edge of a
0.3 ha deciduous forest remnant in a residential neighborhood of Duluth, Minnesota. It was growing with Rubus idaeus, Parthenocissus vitacea, Elymus repens, and Solanum dulcamara in heavy shade of large trees (Acer saccharum) for the first half of the day, but exposed to the sun in the afternoon. The five stems of A. sativum wererootedveryclosely togetheras if acompoundbulbhad been discarded there and taken root. No other garden discards were seen with it. The shoots reached 8 dm height. The soil is loamy and well-drained. Diagnostic Characters. Allium sativum may be distinguished from other Al- lium taxabythecombinationofitspaucityofflowers,caulineleavesthatareflat andsolid, non-fibrousbulb coat, and solitarybractwrappingthe immature inflorescence (McNeal and Jacobsen 2002). Populations like the one reported here that normally develop a single layer of cloves in the bulb and a peduncle with topsets, known as hardstem garlics (Volk and Stern 2009), have sometimes been classified as A. sativum var. or subsp. ophioscorodon (Cavagnaro and Galmarini 2007). The Plant List (2013) treats those infraspecific names as synonyms of the preferred A. sativum.
Specimen Citation. Minnesota. St. Louis Co.: Duluth, NE¼ Sec.15, T50N R14w, July 23, 2016, Schimpf 862 (DUL, MIN).
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Bromus hordeaceus L. subsp. hordeaceus Poaceae Soft chess
Significance of the Report. First report of this non-native weed from Minnesota.
Previous Knowledge. The annual/biennial grass Bromus hordeaceus is native to southern Europe and NorthAfrica (Pavlick andAnderton 2007). In North America, it lives as a weed on sites that are disturbed somewhat frequently, and has been found in all but nine states and provinces (Kartesz 2015). Subspecies hordeaceus seems to be the most widespread of four subspecies in NorthAmerica (Pavlick andAnderton 2007). The synonym Bromus mollis was used widely. County records from adjacent states are few (Kartesz 2015) and minimally different from collections made decades ago (e.g., wisconsin State Herbarium 2016; Stevens 1950; Pohl 1966; Van Bruggen 1985), giving little reason to expect that this grass is likely to become invasive in Minnesota.
Discussion. Bromus hordeaceus subsp. hordeaceus was found growing amidst rows of tall ornamental grasses on the campus of the University of Minnesota, Duluth. The individual plants were sparsely distributed across a few squaremeters with ample sunexposure,where the soil surfacewascovered with horticultural bark mulch. Landscape maintenance activity apparently eliminated all of them by summer 2016.
Diagnostic Characters.Amongtheannual brome grasses, B. hordeaceus has lemmas 1.5–2.5 mm wide in side view, with panicle branches that are shorter than their spikelets and that stand erect or are ascending. The result is a tightly arranged panicle. Subspecies hordeaceus may be distinguished by its longer lemmas and by straight awns that are thicker at the base (Pavlick andAnderton 2007).
Specimen Citation. Minnesota. St. Louis Co.: Duluth, Nw¼ Sec.14, T50N R14w, July 31, 2013, Schimpf 722 (DUL, MIN).
Buxus sempervirens L. Buxaceae Common boxwood
Significance of the Report. First report of this non-native shrub from possibly outside of cultivation in the upper Midwest.
Previous Knowledge. Buxus sempervirens is a monoecious broadleaf evergreen native to southern Europe, southwest Asia, and northwest Africa (Rehder 1960). It is planted as an ornamental for its foliage and is used in floral arrangements or in evergreen wreaths. Numerous horticultural forms have been selected, some of which can grow into small trees (Rehder 1960). Many U. S. cultivars of Buxus now have complex hybrid ancestry (Morton Arboretum 2016). Although the flowers are not conspicuous to humans, they are insect-pollinated, andboththestaminateandpistillateonesproducenectar(Von BalthazarandEn- dress 2002). The toxic foliage (references in Burrows and Tyrl 2001) is disfa
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vored by deer (U.S. National Arboretum 2016), which may contribute to an increase in the frequency of planting. The species has been occasionally reported from outside of cultivation in the eastern United States, largely from southern NewEnglandtoAlabama(Kartesz2015). Noneofthosereportswouldappearto be an old one, given the absence of Buxus in Small (1933), Fernald (1950), and Gleason and Cronquist (1991). Because it is slow-growing, quite visible when neighboring deciduous species are leafless, and not spread by birds, B. sempervirens seems unlikely to become a troublesome invasive species.
Discussion. Two vigorous shoots of B. sempervirens, each about 1 m tall with basal stem diameters of 3 cm, were found on the margin of a cemetery in Duluth, Minnesota. There were no other ornamental shrubs or herbs close by. The stems wererootedafew cmapartin loamygroundimmediatelynext tothenorthsideof the bole of a Pinus resinosa tree that was about 18 m tall and 41 cm diameter at breast height. The position close to the P. resinosa tree may have protected the B. sempervirens from mowing. There was considerable summer shade from a woodlot immediately to the south.Athird shoot, 2.5 cm diameter at the base and similarly close to the other two, was dead except for a few healthy-looking branches near the ground. The three shoots may be part of the same genet, because the speciesisknowntoproducesuckers(Poyarkova1949). ByAugust,thetwovigorous shoots produced seeds with fully developed embryo and endosperm. whether the B. sempervirens was deliberately planted there is uncertain. These plants may have established from seed that was dispersed from a grave decoration. If they wereplantedthereintheeraoftheburials,they have survivedfora longtime: the dates of death on the nearby grave markers are from 1900 through 1912.
Diagnostic Characters. Buxus has thick, opposite, entire leaves; B. sempervirens has blades 1.5–3 cm long and about half as wide (Boufford in press). The only other species of Buxus commonly cultivated in the region is B. microphylla (Bailey 1949; Rehder 1960). The latter differs in having young stems that are more glabrous and more prominently winged and leaves that are broadest above the middle (Bailey 1949).
Specimen Citations. Minnesota. St. Louis Co.: Duluth, Sw¼ Sec.1, T50N R14w, fruiting, June 25, 2015, Schimpf 819 (DUL, MIN); same location, flow- ering,April 21, 2016, Schimpf 849 (DUL, MIN).
Centaurea diffusa Lamarck Asteraceae Tumble-knapweed
Significance of the Report. First vouchered report of this non-native weed from Minnesota.
PreviousKnowledge. Centaurea diffusa isanherbaceousannual,biennial,or short-lived perennial native to southeastern Europe (Keil and Ochsmann 2006). The single stem tends to fracture near the base at the end of the growing season, allowing the finely-branched crown to be tumbled by wind across open spaces, thereby dispersing achenes. The species is designated as a noxious weed by every state in the western conterminous U. S. and is recorded from farther east,
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including from many counties in Michigan (Kartesz 2015). Although Kartesz (2015) displayed seven counties in Minnesota as part of the known distribution, allsevenarebasedonpublicreportstoaninvasivespecieswebsite,andthereare no specimens from those counties at DULor MIN.
Discussion. Approximately 100 plants of C. diffusa were found rooted in limestone railroad ballast of an inactive spur track in Duluth, Minnesota, which is not in one of the counties reported in Kartesz (2015). There was extensive thinly vegetated land immediately adjoining the strip of ballast, but no individuals of C. diffusa were seen outside of the ballast. Rosettes and flowering shoots werebothcommon.TheMinnesotaDepartmentofAgriculturebegananeffortto eradicate this population, which was still well-established as of August 2016. Hybridization with the more common C. stoebe subsp. micranthos, spotted knapweed, to produce the fertile hybrid C.×psammogena is well-known (Keil and Ochsmann 2006), and C. stoebe subsp. micranthos was present at this site. The dark-tipped phyllaries on some plants (Schimpf 733) may result from intro- gression of genes from C. stoebe subsp. micranthos. The plants collected as Schimpf 733 appear not to be C.×psammogena, however, because they lack elongated corollas on the marginal florets, have at most a vestigial pappus, and the phyllary spines are of normal length (Keil and Ochsmann 2006).
Diagnostic Characters. Among the species of Centaurea that have phyllary spines measuring 3–4 mm or less, C. diffusa may be recognized by its non-reflexed spines on an involucre 5 mm in diameter or less (Keil and Ochsmann 2006). Corollas of the marginal florets are not longer than the others in the same head and are usually white, although pink or purplish variants are sometimes present. The occasional occurrenceof white corollasin C. stoebe subsp. micranthos (KeilandOchsmann 2006) mayaccount forreportsof C. diffusa fromother Minnesotacounties,althoughthemarginalfloretsofC. stoebe subsp. micranthos havecorollas that are conspicuously lengthened.After the growing season,these two species may be distinguished at a distance by observing that the phyllaries of C. stoebe subsp. micranthos are spread, exposing the bristly receptacle, whereas the heads of C. diffusa areconstricted towardtheirtip,obscuringthereceptacle. we do not know what C.×psammogena looks like at the same stage.
SpecimenCitations. Minnesota. St. LouisCo.:Duluth, Sec.18,T49NR14w, flowering, August 18, 2013, Schimpf 727 (DUL, MIN); same location, mature achenes, August 27, 2013, Schimpf 732 (DUL, MIN); same location, phyllaries with dark tips and spines,August 27, 2013, Schimpf 733 (DUL, MIN).
Clematis recta L Ranunculaceae Erect clematis
Significance of the Report. First report of this non-native ornamental from outside of cultivation in Minnesota.
Previous Knowledge. AEuropean native (Tutin andAkeroyd 1993), Clematis recta is an herbaceous perennial to 1.5 m tall. It is introduced in NorthAmerica for ornamental use, and has escaped to fields and thickets in New York and
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Ontario (Moreno and Essig 1997) and in New Hampshire (Kartesz 2015). The genus Clematis is poisonous (Hardin andArena 1974), but documented poisonings of humans or domestic animals seem to be rare (Burrows and Tyrl 2001); historical medicinal applications are summarized by Grieve (1931).
Discussion.Afewdozenstemsof C. recta werefoundintallherbaceousvegetation near a residential neighborhood in Duluth, Minnesota. This population appeared to be self-perpetuating and to be spreading slowly on this sunny, well- drained, loamy site, presumably originating from cultivation in the neighborhood. Fruit production was plentiful. As is typical in the genus (Pringle 1997), the petioles and rachises of the leaves had twined upon contact with conspecific plants or with other species, thereby helping many of the clematis plants to maintain heights of about 1.5 m. Some stems were reclining. Grey-wilson (2000) statedthat wildplantsin the native rangetend tobeshorterandtoexhibit greater self-support in comparison with cultivated examples.
Diagnostic Characters. Clematis recta has hollow aerial stems that die after each growing season, white perianths, fragrant flowers, and achenes with pronounced rims. It may be distinguished from the introduced and naturalized species C. terniflora by the latter’s climbing to a few meters height with perennial stems (Moreno and Essig 1997). In August 2016, the plants looked similar to those of the two previous years, with no evidence that stems had survived a previous winter or grown taller or thicker.
Specimen Citations. Minnesota. St. Louis Co.: Duluth, NE¼ of Nw¼ Sec. 5, T49N R14w, in flower, July 19, 2014, Schimpf 779 (DUL, MIN); same location, mature achenes,August 30, 2014, Schimpf 797 (DUL, MIN).
Coriandrum sativum L. Apiaceae Coriander or cilantro
Significance of the Report. First report of this non-native herb from outside of cultivation in Minnesota.
Previous Knowledge. Coriandrum sativum is a native of the Mediterranean area of Africa andAsia (Tutin 1968). This annual is cultivated for flavorings in the forms of cilantro (leaves) and coriander (dried fruits). Reports of its occurrence outside of cultivation are widely scattered in the United States and eastern Canada (Kartesz 2015).
Discussion. Afew plants of C. sativum were found flowering in sand several meters from the Lake Superior waterline. Residential gardens behind high solid fencesa few metersawaycouldbethesource ofseeds. Itseems unlikelythatthe plants were being cultivated where we found them, because there is substantial public foot traffic in this narrow strip of beach. The plants were elevated well above the water in two areas that lacked other plant species. One occurrence consistedoftwomaturingplantsrootedwithin5mmofeachother,whichweinferred to be the result of germination and survivalby bothmericarps of thesame fruit. Tutin (1968) stated that the mericarps do not separate spontaneously. Apparently this does not prevent the species from spreading. No individuals of C.
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sativum wereseenwhenthesiteswererevisitedin2015and2016,sothespecies does not seem to be perpetuating itself there.
Diagnostic Characters. The obcordate petals are white, pink, or purple, and noticeablylonger(to4mm)ontheouteredgeoftheinflorescence.Thefruitsare nearly globose and can reach diameters of 6 mm (Tutin 1968).
Specimen Citation. Minnesota. St. Louis Co.: Duluth, Minnesota Point, NE¼ofNE¼Sec. 34,T50NR14w,August17,2014, Schimpf 791 (DUL,MIN).
Eruca vesicaria (L.) Cav. subsp. sativa (Mill.) Thell. Brassicaceae Arugula or rocket
Significance of the Report. First report of this non-native herb from outside of cultivation in Minnesota.
Previous Knowledge. Eruca vesicaria subsp. sativa is an annual thought to be native to the lands around the Mediterranean Sea, but its longstanding cultivation and subsequent spread makes its native geographic range somewhat obscure (Tutin 1993). It is cultivated for salad greens and industrial oil, as well as for cooking oil and animal feed in Asia (warwick 2010). It has been collected sparingly from the wild in much of temperate NorthAmerica, but apparently not from Minnesota or wisconsin (Kartesz 2015).
Discussion. Eruca vesicaria subsp. sativa was collected from where it had apparently spread from a garden in rural St. Louis County, Minnesota. There were approximately 100 plants with flowers and young fruits, many in infrequently mowed turf between the garden and a woodland.
Diagnostic Characters. The combination of dark veins in the cream-colored petals, dehiscent non-corky siliques, single-veined silique valves, and seedless beak on the silique distinguishes Eruca vesicaria from other annual species of Brassicaceae in North America (Al-Shehbaz 2010a). Subspecies sativa is separated on the basis of its sepals, which do not persist into fruit maturation, and its obtuse anthers (Tutin 1993).
SpecimenCitation. Minnesota. St. LouisCo.:NorthStarTownship,Sw¼of SE¼ Sec. 22, T53N R13w, September 3, 2013, Pomroy and R. Barnes 2821 (DUL, MIN).
Hesperis pycnotricha Borbás & Degen Brassicaceae Russian dame’s rocket
Significance of the Report. First report of this non-native forb from outside of cultivation in NorthAmerica north of Mexico.
Previous Knowledge. Hesperis pycnotricha is a biennial native to the Black Sea region (Davis et al. 1988) that has spread sparingly from cultivation in Europe (Ball 1993; Costache 2011; Py°
sek et al. 2002). It resembles H. matronalis,
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dame’s rocket, which is widely escaped from cultivation in NorthAmerica (Al- Shehbaz 2010b). BecauseAl-Shehbaz (2010b) used a broad morphological concept for H. matronalis when examining North American collections (Ihsan Al- Shehbaz, personal communication, 2016) it is possible that H. pycnotricha grows as an escape elsewhere in North America. Ball (1993) remarked that the distinctness and rank among the eleven European taxa in the genus, which include these two species, was questionable. Dvorák (1966) documented smaller seeds, pollen, and chromosome number of H. pycnotricha (2n = 14), as compared to H. matronalis (2n = 24), and asserted that H. pycnotricha has smaller flowers. Rollins (1993) included plants with 2n = 14 within his broad concept of
H. matronalis.ThereappearstobenostandardEnglishnamefor H. pycnotricha. The Swedish name rysshesperis translates as “Russian hesperis.” Discussion.Apopulationofafewdozenfloweringandfruitingindividualsof Hesperis scattered on a loamy vacant lot in Duluth, Minnesota appears to be H. pycnotricha. A house had been razed and the land graded on the site a year or two before in preparation for commercial construction. The site was shade-free, well-drained, and occupied by a variety of weedy herbaceous species, perhaps a few of which had been planted for erosion control. Hesperis matronalis, a common escape in the city, was not seen on the site. The year after specimens were collected,muchofthesoilwasremoved toreducethe elevation,andthesitewas paved for parking. The population may be regarded as extirpated, although we donotknowwherethesoilwasmoved.Theplantsmayhavedescendedfromornamentals at the residence prior to razing.
Diagnostic Characters. Plants were 7–9 dm tall in flower, with a taproot to 10mm diameter anda stiff stem. Mid-to upper-caulineleaveswere erect, clasping, and sessile. This accords with the treatment of Ball (1993), who described such leaves on H. matronalis as short-petiolate and non-clasping. Al-Shehbaz (2010b) described such leaves of H. matronalis as short-petiolate, whereas Rollins (1993) stated that they are often sessile. Pedicels of Hesperis pycnotricha were erect in both flower and fruit. Pedicels with immature fruit were typically held at angles of 30–45° from the rachis, whereas those of H. ma- tronalis herbarium specimens were typically held at angles of 75° or more. The inflorescences of H. pycnotricha thereby look denser from a distance than those of H. matronalis. The differences between these species in the angles at which the pedicels are held persisted in maturity. The more erect habit could have been the result of the brightly lit site. Dvorák (1966) cites Tsvelev as contrasting the steppe habitat of H. pycnotricha in its native range with the shadier, moister habitats foritscongenersinthe (nowformer) SovietUnion. Many individualsof
H. pycnotricha at our site had anthocyanic herbage. Thisdoesnotseemtobe the result of toxic or infertile soil, because the neighboring species had normal coloration. The median length of seeds measured with an ocular micrometer was 2.1 mm for 57 seeds of H. pycnotricha vs. 3.0 mm for 25 seeds of H. matronalis collectedin thesameyearelsewhere inthe city. The latteris withinthe rangefor H. matronalis reportedbyAl-Shehbaz(2010b),whogives2.5mmasthelowextreme. Rollins (1993) reported the seed length of H. matronalis to be 3–4 mm. The mean weights of these seeds did not closely match the ones reported for either species by Dvorák (1966). About 80% of seeds taken from H. pycnotricha Page 219 2017 THE GREAT LAKES BOTANIST
germinated within a few days on wet paper after dry storage at room temperature. Seedling root tips were fixed and stained using the procedure of Snow (1963), squashed, and observed at 1000×. No more than 14 well-separated condensed chromosomes were seen. Squashes developed from local H. matronalis seed collections yielded 23 or 24 well-separated condensed chromosomes. The petalsof H. pycnotricha seen byus werenot alwaysshorterthanthoseof H. ma- tronalis, contrary tothe description by Dvorák (1966). Hesperis matronalis populations are often characterized by the presence of both white-petalled individuals and pink-or purple-petalled ones. Our population of H. pycnotricha, however, had only purple-petalled individuals, which is consistent with the description in Ball (1993).
Specimen Citations. Minnesota. St. Louis Co.: Duluth, Sw¼ Sec. 23, T50N R14w, in flower, June 29, 2013, Schimpf 710 (DUL, MIN, MO); same location, mature fruit, July 19, 2013, Schimpf 716 (DUL, MIN).
Lavatera thuringiaca L. Malvaceae Tree mallow
Significance of the Report. First report of this non-native ornamental from outside of cultivation in Minnesota.
Previous Knowledge. The tall herbaceous perennial, Lavatera thuringiaca, has escaped from ornamental cultivation in wyoming and North Dakota and in central to eastern Canada (Kartesz 2015). Its native range is from central to southeastern Europe (Fernandes 1968). The genus Lavatera is very similar to Malva, both morphologically and molecularly, and the two may eventually be merged (Hill 2015). Hill (2015) and Kartesz (2015) both report L. thuringiaca from Minnesota only because the collection reported here had been divulged to both of those authors.
Discussion.Abouttwo dozen floweringstems of L. thuringiaca reaching 2 m in height were found outside of cultivation in Duluth, Minnesota. Some were under large deciduous trees, others in open tall herbaceous vegetation between thetreesandaresidentialstreet.Thesoiliswell-drainedandloamy.Threegrowing seasons later, the plants had evidently been pulled out, as inferred from the disturbed condition of the site. The population had produced mature seeds for at least one year, so dormant seeds may have been left on the site after the plants were pulled. Staszewski and Staszewska (1994) reported hard seed coats in 10– 50% of the seeds of this species, which prevents germination until the coat is scarified.
Diagnostic Characters. Fryxell and Hill (2015) distinguish Lavatera from Malva by the elliptical transverse shape of the mericarp of the former, its roundedmericarpedges,itspericarpthatreadilyseparatesfromtheseedcoat,its swollen style base that is persistent on the fruit, and its bractlets below the calyx that are connate for about half their length. Lavatera thuringiaca differs from congeners known to have escaped in NorthAmerica by its herbaceous perennial habit (Hill 2015).
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Specimen Citations. Minnesota. St. Louis Co.: Duluth, Nw¼ of Nw¼ Sec. 12, T50N R14w, in flower, August 11, 2013, Schimpf 725 (DUL, MIN); same location, mature fruit,August 25, 2013, Schimpf 731 (DUL, MIN).
Leymus arenarius (L.) Hochst. Poaceae European lyme grass
Significance of the Report. First report of this non-native perennial grass from outside of cultivation in Minnesota and the first report of it from the coast of Lake Superior.
Previous Knowledge. The perennial grass Leymus arenarius is native to coastal sands of northern Europe. It produces long horizontal rhizomes and has been introduced elsewhere for the purpose of stabilizing sands, or it may also have been unintentionally introduced within the solid ballast of ships (Bowden 1957). In thewestern Hemisphere it has been reported as established or naturalized in southern Greenland and in the north-middle latitudes of NorthAmerica, includingalongsomeoftheGreatLakes(Barkworth2007a)otherthanLakeSuperior. The species is cultivated as an ornamental (Darke 1999). Leymus arenarius is legally regulated as invasive by the State of wisconsin (wisconsin DNR 2015). Older publications use the name Elymus arenarius for this species.
Discussion. Leymus arenarius was found dominating several square meters of sand between a public park building and a Lake Superior beach in Duluth, Minnesota. All shoots were non-flowering. Bond (1952) characterized the species as flowering infrequently in many parts of its native range and as routinely reproducing by dispersed rhizome fragments. The Duluth colony was almost fully surrounded by, but did not extend into the area directly under, taller native woody vegetation. we suspect that the species had been introduced by planting activity intended to stabilize the sand many years before. The colony is about 50 m from the edge of the vegetation that can be reached by storm waves.
Diagnostic Characters. The structural features usually used for identification (Barkworth 2007a) were not available because of the lack of flowering culms. The leaves were thickly glaucous on both sides with stiff blades up to 16 mm wide, the adaxial sides of which were deeply, closely, and uniformly ribbed. Although Barkworth (2007a) described L. arenarius as having blade widths up to 11 mm, Bond (1952) indicated that 2 cm is the upper limit. Leymus mollis is a similar species that might be expected to occur here. This NorthAmerican native has been collected from Lake Superior shores in Ontario (Bowden 1957) and Michigan (Voss and Reznicek 2012). The auricles of Leymus mollis can attain 0.7 mm in length (Barkworth 2007a), whereas those of the Duluth material were 2–3 mm long. we did not find any published reports of auricle dimensions for L. arenarius. Bond (1952) described the auricles as conspicuous. Bowden (1957) reported that the abaxial epidermis of the blade of L. mollis had less conspicuous stomata than that of L. arenarius, but did not provide an illustration. Leymus arenarius isoctoploidand L. mollis istetraploid(Bowden1957);thus,if the nuclear genome of L. arenarius is actually the larger one we would expect
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FIGURE 1. Brightfield photomicrograph of acetate film peeled from abaxial epidermis of blade of Leymus arenarius from Greenland (V. Garlough s.n., DUL). Numerous pairs of guard cells with prominentsubsidiarycellsarevisible. The image representsaportionofthe peel1.3mmby1.0mm. Photograph by D. J. Schimpf.
the guard and subsidiary cells of L. arenarius stomata to be longer (Beaulieu et al. 2008) than those of L. mollis. we examined acetate impressions of epidermises (Hilu and Randall 1984) of the Duluth colony with transmitted light, at 40×, 100×, and 400×, as well as those of herbarium specimens of L. arenarius andL. mollis thatcouldbereadilyidentifiedfromtheirfruitingculms. Beforewe applied the dissolved acetate, the abaxial leaf surface was rubbed with acetone- wetted cotton to remove cuticular wax. In the herbarium material, the stomatal apparatus of L. arenarius was much more visible than that of L. mollis. The stomatal apparatus of the Duluth field material resembles that of L. arenarius much more closely than it does that of the herbarium specimens of L. mollis (Figures 1–3). Figure 3 is also representative of the epidermis of the other three collections of L. mollis that we examined. The stomatal appearance (Bowden 1957) and gross blade morphology (Barkworth 2007a) of the introduced Eurasian L. racemosus are like those of L. arenarius. The ligules of the Duluth plants were as much as 1mm long, which is within the range of L. arenarius but below the 1.5–2.5 mm range of L. racemosus (Barkworth 2007a).
The gross vegetative morphology of Leymus arenarius somewhat resembles that of Ammophila breviligulata (Barkworth 2007b), a native species that is abundant on Great Lakes coastal sands, and non-flowering robust glaucous variants of the latter species could resemble lyme grass from a distance. Barkworth (2007b) described A. breviligulata ligules as being 1–3 mm long, whereas those
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FIGURE 2. Brightfield photomicrograph of acetate film peeled from abaxial epidermis of blade of Leymus arenarius from Duluth, Minnesota (D. J. Schimpf 824, DUL, MIN). Numerous pairs of guardcellswithprominentsubsidiarycellsarevisible. Theimagerepresentsaportionofthepeel1.3 mm by 1.0 mm. Photograph by D. J. Schimpf.
FIGURE 3. Brightfield photomicrograph of acetate film peeled from abaxial epidermis of blade of Leymus mollis from Kugluktuk, Nunavut (formerly Coppermine, NorthwestTerritories), Canada (W.
I. Findlay 244, DUL). Guard cells and subsidiary cells are much less obvious than in Figures 1 and 2. The image represents a portion of the peel 1.3 mm by 1.0 mm. Photograph by D. J. Schimpf. Page 223 2017 THE GREAT LAKES BOTANIST
oftheDuluthplantsthatwedeterminedas L. arenarius werenomorethan1mm long. The blades of Ammophila breviligulata are 8 mm wide or less (Barkworth 2007b). The most important distinction, however, is that the genus Ammophila lacks auricles (Barkworth 2007b).
SpecimenCitation. Minnesota. St. LouisCo.:Duluth,MinnesotaPoint,SE¼ Sec. 2, T49N R14w,August 17, 2014, Schimpf 806 (DUL, MIN).
Malus ×robusta (Carr.) Rehder Rosaceae Hybrid Siberian crab apple
Significance of the Report. First report of this non-native tree from outside of cultivation in the upper Great Lakes region.
Previous Knowledge. Malus ×robusta is the product of hybridization between the Asian deciduous trees Malus baccata, Siberian crab, and M. prunifolia, Chinese crab (Rehder 1960). The parent species are planted in NorthAmerica as ornamentals, and deliberate crosses between them are made in the nursery industry. Both of the parent species are also grown from seed as rootstocks for
M. pumila (Dickson 2014) and may develop sprouts from below the graft that could flower. Malus ×robusta has been reported from outside of cultivation in one county of southeastern Ohio (Vincent et al. 2011). Kartesz (2015) indicates thatthisistheonlyNorthAmericanrecordfromthewild,whereasUSDANRCS (2016) indicates that this nothospecies also occurs in one or more unspecified counties of NewYork. Discussion. A single Malus ×robusta tree was found growing vigorously on public primitive recreational land in Duluth, Minnesota, within several hectares of shallow loamy soil and anorthositic bedrock exposures (Miller and Green 2008) that slope gently northward toward cliff tops. The associated plant species were largely native. The approximately 1 km distance of this location from current or evident past settlements supports our inference that M.×robusta was dispersed there by a wild bird or mammal. The tree consisted of three trunks, each about 15 cm indiameterand anatomically connected toeachother near the base, and numerous basal sprouts. The crown reached a height of 4–5 m, and there werenotallertreesnearby.Thefruitshadwell-developedseeds,butnoseedlings of Malus were seen nearby. The flesh of the fruit in late September was yellow, crisp, juicy, and tart-sweet, but not bitter.
Diagnostic Characters. The long-stalked fruits that lack a calyx and are about2cmindiameteraredistinctive(Rehder1960).Accordingtotheliterature, there may be inconsistent retention of the calyx (Rehder 1960), but none of the dozens of fruits examined from this tree exhibited that character. The fruits were glossy yellowish green, often with a red cheek, at the time of collection, becoming almost wholly red by late September. Some fruits and leaves reddened in the plant press. The fruits were impressed on both ends, with fresh diameters of 21– 26 mm that were about 1.15 to 1.25 times their length. The pedicels were 3–4.5 cm long.According to Cuizhi and Spongberg (2003), M. prunifolia var. prunifolia lacks sepals in fruit, the fruits are 2–2.5 cm diameter, and the pedicels at ma
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turity are 2–3.5 cm long, but the fruits of that species are not impressed at the apex (Rehder 1960). The fruits of M.×robusta look like domesticated cherries dangling from the branches, and Stace (2010) referred to the species as cherry crab.
Specimen Citations. Minnesota. St. Louis Co.: Duluth, Nw¼ Sec. 6, T49N R14w,fruiting,August 21,2016, Schimpf 867 (DUL, MIN);sametree,withfra- grant flowers, June 1, 2017, Schimpf 883 (DUL, MIN).
Nepeta racemosa Lam. Lamiaceae Racemed catnip
Significance of the Report. First report of this non-native ornamental from outside of cultivation in Minnesota.
Previous Knowledge. Nepeta racemosa is an herbaceous perennial with blue-violet flowers native to the Caspian-Caucasus region (Sell and Murrell 2009). It is cultivated as an ornamental, often under the name N. mussinii (e.g., Bailey 1949), or as a source of essential oils (Pistrick 2006). Just a few North American occurrences outside of cultivation have been reported—from Quebec, Ontario, and from one county in each of New York, wisconsin, Colorado, and wyoming (Kartesz 2015). Nepeta racemosa has generally not been included in identification manuals for plants outside of cultivation in NorthAmerica.
Discussion. One plant with 10 flowering stems was observed in open herbaceous vegetation on dunal sand in Duluth, Minnesota. It was in an apparent old dump site for yard and garden debris from the nearby residential neighborhood, situated in a low (but not wet) position in a matrix of Ammophila breviligulata with the latter’s normal shoot density. The site, which is on public land, did not give the impression that it had ever been a “satellite garden.” In August 2016, there were about twice as many flowering stems as in the previous year, all still rooted close together.
Diagnostic Characters. Among the blue-flowered Nepeta commonly grown in North America, N. racemosa may be distinguished by its cordate leaf blades lessthan3cmlong(SellandMurrell2009)andbypetiolesthatarelessthanhalf thebladelength.Themostsimilarcultivatedspeciesisprobablythehorticultural interspecifichybrid N. ×faasenii,whichhascuneatebladebasesandseldomproduces fruit (Sell and Murrell 2009). Numerous mature nutlets were collected from the Duluth plants onAugust 1, 2015, but no more than two full-size nutlets were found to have developed from the four ovules in any one flower. The nut- lets are tuberculate and dark brown with a bright white scar near their base. Nepeta cataria, the widely naturalized common catnip, has whitish corollas. Post-flowering plants can be distinguished by the purple calyx nerves and lobes of N. racemosa, leaves of N. cataria that have blades longer than 3 cm and petioles about half as long (Sell and Murrell 2009), and the lack of tubercles on the nutlets of N. cataria (Budantsev and Lobova 1997).
Specimen Citation. Minnesota. St. Louis Co.: Duluth, Minnesota Point, Nw¼ of Nw¼ Sec. 12, T49N R14w, July 13, 2015, Schimpf 824 (DUL, MIN).
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Origanum vulgare L. Lamiaceae wild marjoram
Significance of the Report. First report of this non-native herb from outside of cultivation in Minnesota.
Previous Knowledge. The culinary herb Origanum vulgare is a rhizomatous perennialnativetoEuropethathaslongbeencultivatedinNorthAmerica. Itses- cape to the wild has been reported from many northeastern and western states andineastern andwesternCanada,butscarcelyfrom themore central statesand provinces (Kartesz 2015). This species is often referred to as oregano, but the food ingredient that is well-known in NorthAmerica by that name is sometimes derived from other taxa (Calpouzos 1954). In addition to the use of its leavesfor flavoring, O. vulgare is valued for ornament and for use in fragrance mixtures (Kew Royal Botanic Gardens 2016).
Discussion. A population of Origanum vulgare was discovered on a steep weedy street-side bank in a residential neighborhood of Duluth, Minnesota. The soil was loamy and the plants were exposed to morning sun. This occurrence likely represents persistence after abandonment of cultivation, and perhaps short- distance spread. The part of the population not under woody cover was occasionally trimmed down with the rest of the rank vegetation, but not close to the ground. Its abundance in the summers of 2015 and 2016 appeared to be comparable to that in 2014. Plants were localized in dense patches that each covered about one-tenth to a few tenths of a square meter, and that collectively covered a few square meters. Flowering began in the second half of July. The population containedplantswithreddishpinkcorollasandotherswithwhitecorollas,thelatter being much more common. The flowers with reddish corollas are subtended by bracts with a reddish purple overcast, whereas those with white corollas are subtended by pale green bracts. Major floras for the region (Fernald 1950; Scoggan 1979; Gleason and Cronquist 1991; Voss and Reznicek 2012) and a popular field guide (Newcomb 1977) used the reddish colors as a diagnostic character state,butthefrequentpale-huedplantsatDuluthfiteasilywithinthevariationdescribed for the native range (Fernandes and Heywood 1972). Both color forms later had plentiful matured nutlets, often three or four in the same flower.
Diagnostic Characters. Origanum vulgare has woody shoot bases (Fernandes and Heywood 1972). The plants at the Duluth site were 7–8 dm tall in flower.Theleafbladeswereupto4cmlong,ovateandnearlyentire,onpetioles up to 1 cm. The inflorescence has round-topped clusters of flowers with sub- tending bracts, usually on three long branches. The calyx is regular, with a villous throat. The corolla has a bilobed upper lip and a trilobed lower lip. The upper two stamens reach the end of the corolla tube; the lower two extend well beyond it. The most similar species, O. heracleoticum, which is reported as es- capedinBritishColumbia(Kartesz2015),hasinflorescencebractsthataremore densely glandular and shorter (2–3 mm vs. 4–5 mm) than those of O. vulgare (Fernandes and Heywood 1972).
Specimen Citations. Minnesota. St. Louis Co.: Duluth, NE¼ of NE¼ Sec. 15, T50N R14w, white-flowered and green-bracted, August 11, 2014, Schimpf 787 (DUL, MIN); same location, pink-flowered and purple-bracted, August 11, 2014, Schimpf 788 (DUL, MIN).
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Rosa canina L. Rosaceae Dog rose
Previous Knowledge. Species of Rosa introduced in NorthAmerica include
R. canina, a tall deciduous non-rhizomatous shrub native to Europe, Asia, and NorthAfrica (Lewis et al. 2014) that is commonly used as a rootstock for grafting (Rehder 1960). The widespread NorthAmerican distribution outside of cultivation is mapped at Kartesz (2015). It has a pentaploid somatic caryotype, which, according to Klášterský (1968), is the result of meiotic behavior that leadstoprogenyroutinelyderiving7chromosomesfromthepollenand28chromosomes from the ovule. This mechanism of sexual reproduction is extremely rare among higher plants, but is also known in other species of Rosa section Caninae (Grant 1971), the section to which R. canina belongs. Discussion. Rosa canina was common over perhaps 20 m2 in a clearing of about 500 m2in a woodland composed of both evergreen conifer and deciduous angiosperm trees in Duluth, Minnesota. The wooded area covered about 3 ha between a residentialneighborhood and a commercial neighborhood. The soil of the clearingwasshallowamidstscatteredsmallbedrockexposures.Theothershrubby or herbaceous species in the clearing included both native and non-native taxa. Fruiting of R. canina was sparse in 2014, but the fruits that were produced were filled with plump achenes. Fruits were more abundant inAugust 2016.
Diagnostic Characters. The arching stems reached about 2 m in height and as much as 2 cm in basal diameter. The prickles are stout and recurved and are in pairs below the adnate stipules. The petals of these plants were 2 cm long and light pink, although white or rose petals have been reported for this species (Lewis et al. 2014). The glabrous scarlet hips were 2 cm long and 1.5 cm diameter, thickened around the orifice, with the styles not exserted. The sepals were still on the fruit in the September collection. Some sepals have long lanceolate appendages, but others on the same fruit lack these. Sepals are abaxially eglandular. The leaves were glabrous and abaxially eglandular.
Specimen Citations. Minnesota. St. Louis Co.: Duluth, NE¼ Sec. 14, T50N R14w, flowering, July 16, 2014, Schimpf 775 (DUL, MIN, MO); same location, fruiting, September 12, 2014, Schimpf 800 (DUL, MIN, MO).
Rosa spinosissima L. Rosaceae Scotch rose
Previous Knowledge. Rosa spinosissima is a medium-height deciduous rhizomatous shrub native to Eurasia (Lewis et al. 2014). Many older publications use the name R. pimpinellifolia for this taxon. It has escaped from cultivation in many states of the Midwest and New England, as well as in eastern Canada (Kartesz 2015).
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Discussion. Apatch of R. spinosissima in Duluth, Minnesota apparently represents an escape from cultivation and has expanded in tall herbaceous vegetation. This is on an open south-facing loamy slope below a residential neighborhood and above a school building. The colony appeared to be spreading slowly down the hill by means of rhizomatous extension in a compact “phalanx” (Lovett Doust 1981) pattern. This patch dominated at least 30 m2 at the time of collection. The fruits contained large achenes, but we do not know whether local reproduction had occurred through seed germination.
Diagnostic Characters. The plants were about 1 m tall and grew in dense patches.Thepricklesaremostlystraightandnotespeciallystout.Theleafletsare 7–9perleafandnomorethan1.5cmlong,whichgivestheplantafiner-textured appearancethanthatofmostotherspeciesof Rosa.Theflowersaresolitary,with a glabrous, subglobose hypanthium. The petals in this colony were pure white, although yellow and pink phenotypes are also known in cultivation (Bailey 1949). The fruits were very abundant, with globose hips that matured black-purple and reached 15 mm in diameter. The sepals, which lack appendages, remained on the ripe fruits.
Specimen Citations. Minnesota. St. Louis Co.: Duluth, NE¼ of Nw ¼ Sec. 5,T49N R14w, flowering, June 28, 2014, Schimpf 766 (DUL, MIN, MO); same location, fruiting,August 30, 2014, Schimpf 798 (DUL, MIN, MO).
Salvia ×sylvestris L. Lamiaceae Hybrid clary
Previous Knowledge. Salvia ×sylvestris, an herbaceous perennial, is a partially fertile (Stace 2010) horticultural cross of the European natives, S. nemorosa and S. pratensis. It is cultivated for ornamental use, and blue is the commonestcorollacolor. ItisknownoutsideofcultivationinNorthAmerica,including in states and provinces that adjoin Minnesota (USDANRCS 2016). The name S. sylvestris has been used to refer to S. nemorosa (e.g., Fernald 1950).
Discussion. Dozens of individuals of S. ×sylvestris were found in a public park in a commercial district of Duluth, Minnesota, evidently derived from seed dispersed fromplants ina nearby ornamentalbedthat had been neglected. Many plants were rooted in cracks or joints in the cap of an old stone retaining wall downslope from the weedy bed, and many others were established in well- drained turf near the bed. Some of these escaped progeny were maturing seed in light shade or full sun, whereas many others were non-flowering. Three years later, S. ×sylvestris was still well-established and flowering in both settings. In 2016, S. ×sylvestris was also found in turf near a different ornamentalbed where this species was being grown, about 75 m away from the first one. The bed near thislaterfindwascurrentlymaintained,andtheturfappearedtobemowedmore frequently.Again, both flowering and non-flowering shoots were in this turf, al
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beit fewer than in the first area. The stems in the turf had been cut by mowing. The species was absent from the area between the two collection sites.
Diagnostic Characters. Like S. nemorosa, S. ×sylvestris has corollas less than15mmlongandpurplefloralbracts;like S. pratensis, S.×sylvestris hasjust afewpairsofcaulineleaves,whichbecomemuchsmalleratsuccessivelyhigher nodes (Bailey and Bailey 1976). Some of the Duluth plants had green floral bracts,andtheothershadamixtureofgreenandpurplefloralbractsonthesame individual.
Specimen Citations. Minnesota. St. Louis Co.: Duluth, Sw¼ Sec. 23, T50N R14w, in stone crevices, July 14, 2013, Schimpf 714 (DUL, MIN); same quar- ter-section, in turf, July 20, 2013, Schimpf 719 (DUL, MIN); same quarter-section, in turf near statue, September 3, 2016, Schimpf 873 (DUL, MIN).
Spiraea japonica L.f. Rosaceae Japanese spiraea
Significance of the Report. First vouchered report of this non-native shrub from outside of cultivation in Minnesota.
PreviousKnowledge. Spiraea japonica isadeciduousshrubnativetoChina, Japan,andKorea(Lis2014). ItisplantedinNorthAmericaasanornamentaland has escaped to the wild in many eastern states as well as in Ontario and Nova Scotia(Kartesz2015). RamseyCounty,MinnesotaismappedbyKartesz(2015), one of very few county-specific locations for this species in the western Great Lakes states, but there are no voucher specimens of S. japonica at DULor MIN from any Minnesota counties. Spiraea japonica exhibits relatively great variation in its native range (Oi 1965; Zhao-Yang et al. 2002) as well as in many cultivated selections. Spiraea ×bumalda has recently been considered by some (e.g.,wilsonandHoch2009;Lis2014)tobemerelyavariantof S. japonica,but seeThe Plant List (2013) for a contrasting view. Spiraea ×bumalda has been reported from outside of cultivation much less frequently, and a Ramsey County occurrencefor it(Kartesz 2015)likewiseseemsto lack avoucher specimen. The Ramsey County designations for both taxa stem from public reports to an invasivespecieswebsite( Kartesz2015). Spiraea japonica hasbeentaggedasaproblematical invader in part of the eastern United States (Lis 2014; wilson and Hoch 2009).
Discussion. Two individuals of S. japonica were found near a long primitive pathleadingtoapublic overlookstructure onaprominencesouthandeastofthe residential area of Silver Bay, Minnesota. This is well-separated from locations with planted ornamentals. The plants were in shade provided by Populus tremuloides, Betula papyrifera, and Abies balsamea where Diervilla lonicera is also a common low shrub. The soil was shallow, loamy, and well-drained and lay over ophitic olivine diabase bedrock with anorthosite outcrops scattered nearby (Miller 1988). One individual of S. japonica grew right next to the path, and the other one about 8 m away from the path, approximately 100 m from the structure and 300 m from where the other end of the path meets a road. The two
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plants were about 5 dm tall and had rose-colored petals and green leaves; culti- vars with golden or bronze leaves are known to tolerate less shade (Snyder et al. 2000). The dryness of the site may account for the shortness of the stems, in that
S. japonica is characteristically an invader in moister settings and may reach 1.5 m in height (Lis 2014). Diagnostic Characters. Spiraea japonica has a compound corymbose inflorescence that is usually terminal and broader than high, stamens that are much longer than the petals, and divergent follicles. Leaf traits are often used in keys, but they exhibit considerable variation. The leaves of the Silver Bay plants most closelyresembledtheillustrationof S. japonica var. japonica inZhao-Yangetal. (2002). For identification of Spiraea consult Bailey (1949), Rehder (1960), or Lis (2014).
Specimen Citation. Minnesota. Lake Co.: Silver Bay, SE¼ of NE¼ Sec. 31, T56NR7w,9July2016, Pomroy, S. Deodhar, and R. Barnes 2859 (DUL,MIN).
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