626 CICHORIACEAE 
the base. Rays terminated by a nearly straight edge with 5 rather low 
teeth. Fruit striated with an aigrette {pappus) of simple bristles varying 
from deep brown to nearly white. 
Plants more than 14 it. high. 
Flower clusters diffuse. 
Heads with 5 to 6 flowers . . . ve xe 6) uh tarts MNES aLERS ssf 
Heads with 8 to 12 flowers. 
Aigrette deep browns < 2 «us « «© oe Lo) mony UcemmeeneE 
Aigrette straw-color. " 
Involucre bracts with stiff hairs . . . P. serpentaria 
Involucre bracts not hairy . . . . . VP. trifoholata 
Flower cluster spicate. t 
Leaves lobed nearly to midvein . : . . . - «. « « PP. virgata 
Leaves not deeply lobed . . Pe ie at E1007. 
Heads with 20 to 25 flowers See: te SL te. he eee e area 
Plants not exceeding 14 ft. high, 
Leaves 3-divided . . « « 
sly Jo oP abe keene P. nana 
Leaves arrow-shaped. . 
NRIMCR AER, ci. oe dh he See ” P. Boottii 
1. P. altissima, L. (Fig. 1, pl. 167.) Tatu Waite Lettuce. Stem 
straight, rigid, 3 to 7 ft. high, smooth, green or purplish, lower part quite 
leafy, upper with remote leaves. Leaves of various shapes, the lower 
broad, usually deeply lobed, on long leaf-stalks. Heads numerous in a 
terminal diffuse, rather narrow cluster, of subordinate clusters, each con- 
taining about half a dozen heads which are pendulous. Involucre eylin- 
dric, 4 in long, smooth, green. Flowers greenish or yellowish white, 
about 5 to 7 flowers in each head. Aigrette light straw color. Rich 
woods, New England and southward and westward. July-Aug. 
2. P.alba, L. (Fig. 2, pl. 167.) RarrLesnakE Root. WHITE LET- 
TUCE. Stem 2 to 5 ft. high, smooth, purple. Leaves on lower part of stem 
broad halberd-shaped, or varying, 3 to 8 in. long, nearly or quite as wide 
at base. Heads pendulous, each 8- to 15-flowered, in broad diffuse cluster 
of subordinate clusters of 2 to 5 heads. Involucre smooth, of about 8 pur- 
plish bracts and a few smaller ones at the base. lowers greenish or 
yellowish white. Aigrette deep brown. Woods, common. Aug.-Sept. 
3. P. serpentaria, Pursh. Lion’s Foor. Less tall than No. 2; leaves 
similar, but the involucre quite hairy with stiff hairs. Fields and woods, 
New England and southward. July-Oct. 
4. P, trifoliolata, (Cass.) Fernald. (Fig. 3, pl. 167.) Tati Rat- 
TLESNAKE Root. Whole plant smooth. Stem 3 to 9 ft. high. Leaves 
usually 3-divided with the divisions stalked. Heads 8- to 12-flowered. 
Flowers white to yellowish. Woods, Maine, Vermont, New York, Penna., 
and southward. Aug.-Oct. 
5. P. nana, DC. (Fig. 4, pl. 167.) Lion’s Foor. Plant smooth 
throughout, stem erect, from 4 to 15 in. high. Lower leaves 3-parted, the 
divisions generally 3-lobed. Flower heads numerous. Summits of White 
and Adirondack Mountains. Aug.-Sept. 
6. P. virgata, DC. (Fig. 5, pl. 167.) StenpeR RatrrLresNAKE Root. 
Smooth. stem simple, straight, 2 to 4 ft. high. Leaves in general outline 
Jance-shaped, often 10 in. long, lobed nearly to the mid-vein on each side. 
Flower heads in a slender spike often all on one side. Flowers white. 
Sandy soil. New Jersey, southward. Sept.-Oct. 
7. P. Boottii, (DC.) Gray. (Fig. 6, pl. 167.) Boort’s RATTLE- 
