The Flora of the Cayuga Lake Basin 409 



c. Stolons (except in shaded individuals) comparatively short and assurgent, 



more leafy, usually forming dense mats ; basal leaves, especially those of the 



stolons, bright green and glabrous above; pistillate inflorescence of 3-18 



corymbose heads; involucral bracts greenish white, often greenish brown, 



with subscarious, rather narrow, tips ; styles usually white or cream color ; 



staminate plants rare, the involucral bracts with expanded thin petaloid erose 



tips, and the pappus hairs at the summit somewhat dilated, strongly barbellate 



throughout. 2. A. canadensis 



b. Middle and upper cauline leaves subulate-tipped or mucronate, without a scarious 



appendage (except sometimes on the bracteal leaves of the inflorescence) ; 



rosette leaves spatulate or spatulate-obovate, rarely oblanceolate, rounded at 



apex, rarely acute, often 3-nerved beneath toward base, dull and more or 



less hairy, especially on the stolons; (pistillate heads corymbose or glomerate, 



styles not purple). 



c. Stolons rather long, prostrate, leafy with an assurgent tuft of larger leaves 



at apex ; leaves with a rather narrow subpetiolate base, scarcely mucronate ; 



involucre 7-11 mm. high; bracts petaloid, linear-oblong, the outer ones rather 



blunt ; corollas 5-6.5 mm. long ; the longer pappus hairs 5.5-7.5 mm. long ; 



achenes 1.2-1.7 mm. long; staminate plants very rare, with tips of the 



involucral bracts very broadly dilated, firm, petaloid, scarcely erose, and the 



pappus hairs much dilated, barbellate to the tip. 



d. Rosette leaves spatulate or spatulate-obovate, rounded at apex. 



3. A. petaloidea 

 d. Rosette leaves oblanceolate, acute or acutish. 3a. A. petaloidea, 



var. noveboracensis 

 c. Stolons short, immediately assurgent with a terminal tuft of large leaves at 

 apex ; leaves more cuneate, with broader bases, plainly mucronate ; involucre 

 6-7 mm. high ; bracts petaloid or scarious ; corollas 3.7-5 mm. long ; the longer 

 pappus hairs 5.5-6 mm. long; achenes 1.1-1.4 mm. long; staminate plants very 

 rare, the involucral bracts with very broad and blunt petaloid erose tips, those 

 in the variety somewhat narrower, and the pappus hairs scarcely dilated, 

 strongly barbellate throughout. 

 d. Tips of the involucral bracts linear-oblong, mostly obtuse, petaloid. 



4. A. neodioica 



d. Tips of the involucral bracts tapering, acute, usually thinner and more 

 scarious. 4a. A. neodioica, 



var. attenuata 

 a. Rosette leaves comparatively large, 0.7-5.5 cm. wide, with 3-7 somewhat prominent 

 long ribs beneath; middle and upper cauline leaves with firm subulate tips. 

 b. Rosette leaves, at least those of the stolons, dull, hairy above. 

 c. Pistillate involucre 5-7 mm. high ; basal leaves obovate to roundish-oblong- 

 ovate or more rarely oblanceolate, minutely mucronate; pistillate plants with 

 slender stems and 5-12 linear-lanceolate, attenuate, more or less distant, 

 leaves ; involucral bracts often purplish-tinged, with narrow scarious or 

 petaloid tips; corollas often crimson, 2.5-4.3 mm. long; longest pappus 

 hairs 4-5.5 mm. long; mature achenes 1.1-1.5 mm. long; staminate plants 

 common, the tips of the involucral bracts more or less dilated and erose, and 

 the pappus hairs moderately dilated, barbellate throughout. 



5. A. plantaginifolia 

 c. Pistillate involucre usually 8-11 mm. high; basal leaves more strongly mucro- 

 nate ; pistillate plants with corollas 5-7 mm. long ; longest pappus hairs 

 6-9 mm. long; flowering stems stout, with larger, wider, more overlapping 

 leaves. 



d. Rosette leaves spatulate to narrowly spatulate-obovate, with rounded apex ; 

 pistillate plants with 6-15 cauline leaves; outer involucral bracts with 



