150 CAEDUACEAE. 



11. PLUCHEA Cass. Herbs or shrubs. Leaves alternate: blades usually 

 toothed, often prominently veined. Heads borne in corymb-like or glomerate 

 cymes. Involucres turbinate, campanulate, or hemispheric, rather many- 

 flowered: bracts unequal, the inner much longer and much narrower than the 

 outer. Pistillate flowers marginal: corollas filiform. Perfect flowers central: 

 corollas with a funnelform or campanulate throat: lobes triangular to lanceo- 

 late. Pappus a single series of capillary bristles. — Marsh-fleabane, 



Leaf-blades toothed : stems herbaceous. 



Leaf-blades sessile and clasping : plants perennial. 1. P. foetida. 



Leaf-blades neither sessile nor clasping: plants annual. 2. P. ptirpurascens. 



Leaf-blades entire : stems woody. 3. P. odorata. 



1. P. foetida (L.) B.S.P. Plants 3-10 dm. tall: leaf -blades oblong to ovate- 

 oblong, 3-8 cm. long: inner bracts of the involucres 4-5 mm. long: staminate 

 corollas 3.5—4 mm. long. — Lime-sinks, L. keys. — [E. K.] — {Bah., Cuba.) 



2. P. purpurascens (Sw.) DC. Plants 3-14 dm. tall: leaf -blades ovate-lanceo- 

 late to elliptic or oblong, 4-10 cm. long: outer bracts of the involucre ovate, 

 acute; intermediate bracts abruptlv pointed. — Hammocks, U. keys, L. keys. — 

 [E. K.]—(Ber., Bah., Cuba, Ant.)' 



3. P. odorata Cass. Plants mostly 1 m. tall or less: leaf-blades oblong or 

 nearly so, 8-15 cm. long: inner bracts of the involucres 3.5-4 mm. long, obtuse. 

 - — Hammocks and waste grounds, Key West. Xat. of Trop. Am. — (Bcr., Bah., 

 Cuba, Ant.) , 



12. PTEROCAULON Ell. Tomentose or woolly stout herbs. Leaves 

 alternate: blades entire or shallowly toothed, decurrent. Heads borne in con- 

 tiguous or separated glomerate cymes. Involucres rather narrow, densely 

 flowered: bracts unequal, the inner slightly narrower than the outer. Pistil- 

 late flowers marginal: corollas filiform. Perfect flowers central: corollas with 

 a funnelform throat and a long tube; lobes linear or lanceolate. Anthers 

 shorter than the filaments. Pappus a single series of capillary bristles. 



1. P. undulatum (Walt.) Ell. Plants 2-7 dm. tall: leaf -blades oblong to lance- 

 olate, 4-12 cm. long, undulate: involucres 3.5-4 mm. high: lobes of the 

 staminate corollas linear. — Pinelands, L. keys. — [E. K.] — Black-root. 



13. SACHSIA Griseb. Inconspicuously pubescent, slender herbs. Leaves 

 alternate, mostly basal: blades toothed. Heads scattered in open corymbs. 

 Involucres campanulate: bracts very unequal, the inner much longer and some- 

 what narrower than the outer. Pistillate flowers marginal: corollas filiform. 

 Perfect flowers central: corollas narrowly tubular-funnelform: lobes ovate. 

 Pappus a single series of very slender bristles. 



1. S. bahamensis Urban. Plants 1-6 dm. tall : blades of the basal leaves firm, 

 spatulate. 3-7 cm. long, those of the stem-leaves much smaller: involucres 

 peduncled; bracts various, the outer membranous, the inner chaffy, 5-6 mm. 

 long, very narrowly linear: achenes 2.5 mm. long. — Pinelands, L. keys. — [E. K.] 

 — {Bah.j 



14. PAJRTHENIUM L. Coarse herbs, or shrubs. Leaves alternate: 

 blades toothed, pinnatifid, or dissected. Heads inconspicuously radiate. In- 

 volucre depressed to globular: bracts appressed, broad. Kay-flowers usually 5: 

 ligules minute, white or whitish. Lobes of the disk-corollas ovate, ciliate. 

 Anthers longer than the filaments. Achenes flattened. Pappus of 2 or 3 scales 

 or awns. 



