218 NORTH AMERICAN FLORA 
Angles of the fruit continuous, smooth. 
Leaf-blades linear, 2-7 mm. wide; stems glabrous. 
Leaf-blades lanceolate or broader, 10-40 mm, wide. 
Stems glabrous. 
. Stems densely short-pilose. 
Fruit more or less pubescent, sometimes with only sparse pubescence of 
short hairs. 
Leaf-blades sessile or nearly so, or sometimes gradually attenuate to a 
eaeie stout petiole, the blade not sharply differentiated from the 
petiole. 
Leaf-blades linear or lance-linear. 
Perianth deep bright-red, about 4 times as long as the involucre, 
much longer than broad. 
Perianth pink or purplish-red, about twice as long as the in- 
volucre, usually broader than long. 
Stems densely hirsute or long-villous, at least at the base, 
glaucous. 
Stems glabrous below or nearly so. 
Stems glaucous; leaf-blades sessile or gradually narrowed 
to a short, stout or marginate petiole, glaucous or 
glaucescent beneath. 
Stems green; leaf-blades, at least the lower ones, sub- 
abruptly contracted into a slender petiole, bright- 
green. 
Leaf-blades lanceolate or broader. 
Stems densely hirsute, at least near the base, the middle nodes 
sometimes glabrate but the nodes always hirsute. 
Stems puberulent or glabrate, or sometimes pilose or hirsute above 
but not near the base, 
Stems densely puberulent throughout; leaf-blades ovate to 
ovate-deltoid. 
Stems glabrate below or puberulent only in lines; leaf-blades 
mostly lanceolate. 
Angles of the fruit strongly tuberculate or composed of 
distinct tubercles. 
Angles of the fruit continuous, smooth or nearly so. 
Leaf-blades usually broadly rounded at the base or 
even subcordate, those of the lower leaves some- 
times acute at the base; branches of the inflores- 
cence mostly opposite. 
Leaf-blades acute or acuminate at the base; branches 
of the inflorescence mostly alternate. 
Leaf-blades, at least most of them, on long slender petioles, the blades 
usually obtuse to cordate at the base and sharply differentiated 
from the petioles. 
Fruit prominently 5-angulate, the angles smooth or tuberculate; 
stems usually stout, erect or decumbent, and sparsely branched; 
involucres much accrescent in fruit, the lobes equal or nearly so. 
Involucres at anthesis usually glabrous except at the base, 
there short-pilose or puberulent, the lobes glabrous, in fruit 
usually 15-20 mm. broad. 
Involucres at anthesis densely viscid-pilose outside, in fruit 
usually less than 15 mm. broad. 
Stems densely puberulent, pilose, or hirsute below, over the 
whole surface, with stiff hairs. 
Leaf-blades usually twice as long as broad, ovate or 
ovate-oblong, and obtuse at the base; plants tall, erect, 
simple or sparsely branched below. 
Leaf-blades less than twice as long as broad, mostly 
ovate-deltoid or deltoid, usually truncate or sub- 
cordate at the base; plants low, spreading, much 
branched below, the branches mostly divergent. 
Stems puberulent or short-pilose below with weak, 
soft hairs. 
Stems hirsute below with long, stiff hairs. 
Stems glabrous below or puberulent in lines, very rarely 
pilose with weak, soft, viscid hairs. 
Plants suffruticose. 
Plants herbaceous. 
Blades of the upper leaves about as broad as long, 
rounded or very obtuse at the apex; involucres in 
fruit 10-12 mm. long. 
Blades of the upper leaves usually twice as long as 
broad or longer, lance-oblong to linear, com- 
monly long-acuminate to attenuate at the apex; 
involucres in fruit rarely over 8 mm. long. 
Lobes of the involucre oval-oblong, longer than the 
tube, all or most of them rounded at the 
apex, usually pilose with black hairs. 
an 
10. 
12. 
13. 
14. 
15. 
19, 
16. 
17, 
18. 
21. 
20. 
Bo 
[VoLumME 21 
. glabra. 
. exaltata. 
. Carletoni. 
. coccinea, 
. gausapoides. 
. linearis. 
. decipiens. 
. hirsuta, 
. pauci flora. 
. albida. 
. lanceolata. 
. aggregata, 
. nyclaginea. 
. coahuilensis. 
pumila. 
, rotundifolia. 
. Suffruticosa. 
. Grayana. 
