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THE MICHIGAN BOTANIST
Vol. 38
sparse and abruptly reduced in size (50% to 25% size of cauline leaves). Capitula 2-3.5 (4) cm in diameter with rays fully extended. Involucre campanulate,
(6) 8-12 (15) mm long (Jones 1989), typically not graduated. Phyllaries slender,
long-attenuate, 6-10 (15) mm long, flexible, herbaceous. Ray florets 20-40 (to
60), 12-18(20) mm long, lavender to purple. Disk florets 30-50, narrow but dilated at throat, (4.5) 5-6 mm long, limb turning from cream or yellow to pink or
purple after anthesis. Achenes obconic, (2) 2.5-3.5 (4) mm long and 1 mm or
less across, 1 rib per side. Pappus a single, simple whorl.
Flowering (late August) September-October. Fruiting October-November.
Range extending southward from northeastern states along the Appalachian
mountains to Georgia, northwest into Alberta and westward to Nebraska (Semple 1983); most abundant in the eastern part of its range (Semple 1987). Habitat
predominantly open to moderately shaded, very wet peat substrate.
Aster firmus Nees. Syn. Ast. 25 (1818).
Syn. Aster lucidulus (Gray) Wiegand. Rhodora 26: 4 (1924).
'Smooth-stemmed Aster'
Herbaceous perennial spreading clonally, often forming large colonies. New
shoots emerging singly from long, strongly creeping rhizomes (to 70 cm long).
Stems moderately thin at base (2-8 mm diameter), erect, 50-200 cm tall, anthocyanotic directly above each node. Basal stem portions often hispidulous, but
upper stem (> 30 cm above ground) glabrous with occasional hairs found in decurrent lines from nodes. Leaves of winter rosette small, basal leaves deciduous
at anthesis. Cauline leaves alternate, 5-15 cm long, 2-3 cm wide at widest point,
typically light green, oblanceolate, auriculate clasping; abaxial midvein
glabrous, occasionally hispidulus near tip. Capitulescence densely paniculiform
to corymbiform with crowded heads. Leaves in capitulescence slightly and gradually reduced in size from cauline leaves, crowded, at times overtopping heads.
Capitula 1.5-3.5 cm in diameter with rays fully extended. Involucre campanulate 6-10 mm long, somewhat graduated. Phyllaries often acute, not strongly attenuate, 6-10 mm long, flexible, herbaceous. Ray florets 20-40, 10-18 mm
long, white to pale lavender. Disk florets 30-50, narrow but dilated at throat,
(4.5) 5-6 mm long, limb turning from cream or yellow to pink or purple after anthesis. Achenes obconic, 1.7-3.0 mm long and 1 mm or less across, 1 rib per
side. Pappus a single, simple whorl.
Flowering Early September-October. Fruiting October-November (Jones
1980b, 1989). Range extending southward from northeastern states along Appalachian mountains to Georgia, northwest into Alberta and westward to Nebraska (Semple 1983); more common in the western part of range (Semple
1987). Habitat predominantly open, wet ground, but prone to spread into mesic
mineral soils.
ACKNOWLEDGMENTS
This work was supported by a Calvin Research Fellowship (to D. Warners) with additional financial support provided by the Calvin College Biology Department (to D. Laughlin). We gratefully acknowledge the assistance and direction of Dr. Anton Reznicek throughout this study and appreciate
