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34 THE GREAT LAKES BOTANIST Vol. 57

NOTEWORTHY COLLECTIONS

NEWAND INTERESTING INTRODUCEDVASCULAR PLANTS FOR ONTARIOAND CANADA

Colin J. Chapman Atlantic Canada Conservation Data Centre 146 Main Street Sackville, New Brunswick E4L 1A8

James S. Pringle Royal Botanical Gardens 680 Plains Road West Burlington, Ontario L7T 4H4

Allium tuberosum Rottler ex Spreng. Amaryllidaceae Chinese Chives

Significance of the report. This southeast Asian species is new to the spontaneous flora of Ontario and Canada.

Previous Knowledge. Allium tuberosum is cultivated in China, Siberia, and North America, often for culinary uses, and less frequently as an ornamental (McNeal and Jacobsen 2002; J. Peter, personal communication). It has been reported as occasionally escaping to disturbed areas and roadsides in Michigan, Ohio, Wisconsin, Nebraska, and New England (McNeal and Jacobsen 2002; Vincent et al. 2011; Voss and Reznicek 2012).

Discussion. The specimens here discussed, as well as all those in the following accounts, are the basis for the county records in the list of the vascular plants of Ontario’s Carolinian Zone (Oldham 2017). In 2016 C.J. Chapman collected a clear escape from a vacant lot in the City of Hamilton; a subsequent search of larger Ontario herbaria (TRT, DAO, CAN, HAM) produced two additional specimens. The apparent first spontaneous record of Allium tuberosum in Ontario was collected in 1975 by J. Nyman from a vacant lot in the Greater Toronto Area. Originally identified as A. stellatum Fraser ex Ker Gawl., it was redetermined as A. tuberosum by Michael J. Oldham in March 2017. This species was subsequently collected in 2012 from Haldimand-Norfolk County by J. Schlegel. The question now arises whether these records represent waifs or persistent populations. In 2015 A. tuberosum was found persisting in a former cultural site at Royal Botanical Gardens (RBG) that has been unmaintained since the mid1990s. Its persistence at the vacant site indicates that the species is able to over

1Author for correspondence (colin.chapman@accdc.ca)

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winter in southern Ontario. Multiple records of spontaneous A. tuberosum also suggest that this species has been overlooked, potentially due to its status as an urban weed. Urban areas understandably receive less botanical attention than natural areas, and for this reason we speculate that it may have escaped more often than is reported.

Diagnostic Characters. Allium tuberosum is easily distinguished by its white flowers on erect pedicels that bloom from late August into October, much later than other Ontario species of Allium L. (Voss and Reznicek 2012). Allium stella- tum, with which the first record was confused, has purple flowers that face in all directions (Voss and Reznicek 2012).

Specimen Citations. Ontario. Greater Toronto Area; Corner of Denlow Blvd. and Banbury Rd. on south side. Don Mills. Latitude: 43°45¢N, Longitude: 79°21¢W. Disturbed vacant lot and adjoining fence-lines and sidewalks. September 20, 1975. Judy Nyman s.n. (TRT).

Haldimand-Norfolk County: Lake Erie shore at foot of Rte. 12 (Fisherville Road). between hamlets of Rainham Centre and Selkirk. Crack in boulder break- wall between beach and road. In full sun. Small clump with strong onion smell. Flowers white, midveins of tepals greenish and inconspicuous in life. Additional clumps further east along breakwall. Latitude: 42°49.321¢N, Longitude: 79°52.838¢W. Associates: Acer negundo, Dipsacus fullonum, Solidago canaden- sis, Cichorium intybus, Coronilla varia. August 30, 2012. J. Schlegel 1203 (HAM).

Halton Regional Municipality: Southern edge of Hendrie Valley Sanctuary, adjacent to Unsworth Avenue HV-2015-Polygon 6. Upland mixed cultural site. Garden unmaintained since mid-1990s, exotic herbs/shrubs/trees persisting. Seeded in 2014 with native meadow species. UTM NAD83 17T 591963 4794688 ± 70m. August 27, 2015. N. Cavallin, R. M. Godfrey, C. J. Chapman, C. Burt s.n. (HAM).

City of Hamilton: southwest corner of Wilson Street and Mary Street. Vegetated corner of parking lot; one clump; on very narrow and isolated strip of soil. Latitude: 43°15¢27.7¢¢N, Longitude: 79°51¢47.5¢¢W. Associates: Convolvulus arvensis, Cichorium intybus, Lotus corniculatus, Setaria viridis, Plantago lanceolata. September 28, 2016. C. J. Chapman 2016-157 (HAM).

Cercidiphyllum japonicum Siebold & Zucc. ex J.J. Hoffm. & J.H. Schult. bis Cercidiphyllaceae Katsura

Significance of the report. The first record of Cercidiphyllum japonicum as an escape from cultivation in Ontario and Canada.

Previous Knowledge. Cercidiphyllum japonicum is a dioecious tree native to deciduous forests in China and Japan (Knees 2011). In North America, it has been reported as escaping from cultivation in Massachusetts, Connecticut, New York, Pennsylvania, and Ohio (Haines 2011; USDA, NRCS 2016). Sato et al. (2006) report a maximum seed dispersal distance of more than 300 meters. Cercidiphyllaceae is a monotypic family with a distinctive morphology; APG IV

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(2016) currently places it within the Saxifragales, but others have suggested placing it in its own order (e.g., Swamy and Bailey 1949).

Discussion. Iwanycki et al. (2014) report finding escapes in Cootes Paradise Sanctuary in 2010 and taking a specimen in 2011. We have not been able to locate such a specimen in either the HAM collection or its database. In 2016, several seedlings measuring up to 45 cm in height were discovered at the forest edge of Royal Botanical Gardens’ Cootes Paradise Sanctuary. The young C. japonicum observed were approximately 45 meters from the nearest cultivated female individual. A focused search of the vicinity provided no evidence of seedling establishment within the forest itself. The first author verified reliable images for an additional report of C. japonicum from Nordheimer Ravine, Toronto. The roughly three-feet-tall seedlings appeared in imported soil, although it is unclear whether they were locally escaped from cultivation or transported in the soil as weeds (J. Routh, personal communication). It seems likely that an increased use of C. japonicum in landscaping should result in the discovery of additional escapes from cultivation. Nearly all escapes from cultivation have thus far been found in ruderal habitats; however, the escape observed by Iwanycki et al. (2014) was reportedly discovered along a trail in a deciduous forest. In its native range, C. japonicum is a tree of deciduous forests; it should be monitored in the Great Lakes region for escape into high-quality natural habitat.

Diagnostic Characters. Cercidiphyllum japonicum has distinctive dimorphic leaves. Mature leaves of short shoots have a morphology similar to those of Cercis L., demonstrating the etymology of the generic name. However, they are oppositely arranged and smaller than the leaves of Cercis, which are alternate. Leaves on short shoots are cordate and with crenate margins, while long shoots bear leaves with a shallowly crenate to entire margin. Blade shape varies from elliptic to ovate to deltoid. For a detailed discussion of morphology, see Swamy and Bailey (1949).

Specimen Citation. Ontario. City of Hamilton: On forest edge between Lilac Dell and Cootes Paradise Sanctuary. Four seedlings observed in immediate area. Latitude 43°16¢56.7¢¢N, Longitude 79°54¢18.6¢¢W. June 20, 2016. C. J. Chapman,

J. E. Thompson, and P. Becker 2016-137 (HAM). Corydalis nobilis (L.) Pers. Papaveraceae Siberian Corydalis

Significance of the report. This species is not known to the spontaneous flora of North America (Stern 1997).

Previous Knowledge. Corydalis nobilis is a perennial endemic of central Asia-Siberia, where it inhabits stony slopes and shaded ravines (Shulkina 2004). In Europe C. nobilis is reported as naturalized in Sweden and Finland (Jalas and Suominen 1991). Cullen (2011) notes that C. nobilis is likely the most frequently grown of the taller Corydalis species.

Discussion. Corydalis nobilis was collected from Royal Botanical Gardens’ Woodland Garden in the spring of 2016, prompted by its abundance throughout the cultural forest. It was first collected from this location in April 2009 by A.

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Scovil, N. Iwanycki, and H. Crochetiere, but was treated as a cultivated specimen. However, there is no record of C. nobilis having been acquired by RBG, and its provenance is unknown. The population has been spreading aggressively by seed in recent years, prompting staff to manage it intensively to prevent its migration into Hendrie Valley Sanctuary (C. Briggs, personal communication). Regardless of its method of introduction, it is now a persistent garden weed on RBG property. The aggressive reseeding of C. nobilis is similar to that of C. in- cisa (Thunb.) Pers., a recently reported invasive species in the States of New York, Virginia, West Virginia, Maryland, Tennessee, Washington D.C., and Pennsylvania (Atha et al. 2014; USDA, APHIS 2017). For this reason, botanists are urged to promptly report new records to landowners.

Diagnostic Characters. The flowers of Corydalis nobilis are arranged in a dense inflorescence and have a yellow corolla with dark violet colouration at the tip (Figure 1) (Cullen 2011). The four native species of Corydalis in the Great Lakes region—C. aurea Willd., C. curvisiliqua Engelm. ex A. Gray, C. flavula (Raf.) DC., C. micrantha (Engelm. ex A. Gray) A. Gray—generally do not exhibit this colouration, and they have sparser inflorescences (Stern 1997; Cullen 2011). It is also distinguished from its native, annual/biennial congeners by its robust perennial habit (Stern 1997; Zhang et al. 2008). Corydalis solida (L.) Clairv. (Michigan, Ontario) and C. incisa (New York), two extremely rare introduced species, are both distinguished from C. nobilis by their purple corollas (Voss and Reznicek 2012; Atha et al. 2014).

Specimen Citations. Ontario. Halton Regional Municipality: Woodland Garden. Colour code: RHS 1966, Flowers: Yellow-orange group 17C. Identified by Jim Pringle on May 22 2009. 29 April 2009. A. Scovil, N. E. Iwanycki, and H. Crochetiere s.n. (HAM).

FIGURE 1. A: Inflorescence of Corydalis nobilis (L.) Pers. Note the dense arrangement of flowers and the dark colouration at the tip of the corollas. B: Corydalis nobilis (flowering) competing with Dicentra canadensis (Goldie) Walp., which has smaller leaves with paler colouration. Photos by Philippa Becker.

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Halton Regional Municipality: Royal Botanical Gardens. Woodland Garden, bottom of slope before the gate to Hendrie Valley Sanctuary. Found throughout the Woodland Garden on north-facing slope, down to the lowland and Rifle Range before the gate to Hendrie Valley. Latitude 43°17¢33.1¢¢N, Longitude 79°52¢40.0¢¢W. Associates: Rosa multiflora, Dicentra canadensis. May 10, 2016.

C. J. Chapman, J. E. Thompson, and P. Becker 2016-15 (HAM, DAO). Sorbus intermedia (Ehrh.) Pers. Rosaceae Swedish Whitebeam

Significance of the report. The second Great Lakes region report of Sorbus intermedia, an extremely rare escape from cultivation.

Previous Knowledge. Sorbus intermedia is a medium-sized apomictic tree native to northern and eastern Europe (Warburg and Kárpáti 1968). It is one of a number of species that are widely used in gardening and landscaping for its flowers, decorative fruit, and foliage (Warburg and Kárpáti 1968; McAllister and Taylor 2011). In Canada, it is reported as very rarely escaping to disturbed habitats in British Columbia (Brouillet et al. 2010+, Zika and Bailleul 2014). In the United States, Sorbus intermedia is reported as escaping in Massachussets, and Washington (Zika and Bailleul 2014).

Discussion. A single shrub of Sorbus intermedia was discovered in 2006 by Michael Oldham and Sam Brinker in deciduous woods in the Regional Municipality of Niagara. The identity of the specimen was verified by Peter Zika in 2012. Two additional sterile escapes from cultivation were collected from disturbed habitats near railroad tracks in Niagara in 2007 and in the City of Hamilton in 2016. C. J. Chapman 2016-156 is approximately 750 meters from the closest known cultivated street tree at Stinson Street and Erie Avenue. The cultivated individual was observed with abundant fruit set in the fall of 2016. In its native range, S. intermedia is dispersed by thrushes and waxwings (Rushforth 1999). Likewise, birds may have dispersed the seeds of this apomictic tree in Hamilton, which plausibly explains its movement to the Escarpment Rail Trail. It seems likely that S. intermedia will escape in additional counties in the Great Lakes region where it is cultivated.

Diagnostic Characters. Unlike those of most familiar Ontario Sorbus species, the leaves of S. intermedia are nearly simple, with numerous lobes rather than leaflets (Figure 2) (McAllister and Taylor 2011). It shares this feature with S. hybrida L., another rare introduction in northeastern North America (Brouillet et al. 2010+; Haines 2011). In general, S. intermedia is distinguished from S. hybrida by its leaf morphology: in the latter the basalmost pair of lobes are dissected to the midrib; however, separate basal lobes may also occur on sucker shoots of S. intermedia (McAllister and Taylor 2011). The leaves are also distinguished by the number of lateral vein pairs: 7–9 in S. intermedia, 10–12 in

S. hybrida (McAllister and Taylor 2011). Specimen Citation. Ontario. Regional Municipality of Niagara. Deciduous woods. Whirlpool area, Niagara River. Single sterile shrub at edge of rocky trail through woods; almost certainly non-planted. UTM NAD83 17T 657293

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FIGURE 2. Leaf of Sorbus intermedia (Ehrh.) Pers. on a long shoot with the two basal lobes dissected to the midrib. Note fewer than nine pairs of lateral veins. Photo by Colin J. Chapman.

4776326. July 18, 2006. M. J. Oldham 32980 (MICH, WTU, herb. M. J. Old- ham).

Regional Municipality of Niagara. Niagara Falls Railway Yard, between Whirlpool Road and Victoria Avenue. Disturbed ground along railway tracks. Single 10 ft tall shrub; sterile. UTM NAD83 17T 655972.2756 4776568.5. August 17, 2007. M. J. Oldham and S. Brinker 34927 (WTU, NHIC).

City of Hamilton: Woodland south of Escarpment Rail Trail. Disturbed woodland next to wet depression. One plant in this locality, roughly 110 cm tall; two additional plants were found within 100m, both smaller and in similar habitat. Latitude 43°14¢39.2¢¢N, Longitude 79°50¢51.9¢¢W. Associates: Rhamnus cathartica, Populus alba, Rhus typhina, Toxicodendron radicans, Solidago canadensis, Symphyotrichum lanceolatum, Rosa multiflora, Fraxinus pennsylvanica, Dactylis glomerata, Ageratina altissima, Alliaria petiolata, Ambrosia artemisiifolia. September 19, 2016. C. J. Chapman 2016-156 (HAM).

ACKNOWLEDGMENTS

Michael Oldham provided collection data for his Niagara Sorbus intermedia records, the Toronto Allium tuberosum record, and searched TRT, CAN, and DAO for the taxa here reported. We are very grateful for his help. We also thank Charlie Briggs, Jon Peter, and John Routh for their comments.

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Philippa Becker provided photographs of Corydalis nobilis. Michael Huft and an anonymous reviewer provided helpful comments on the manuscript.

LITERATURE CITED

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