THISTLE FAMILY 833 



FAMILY 134. CARDUACEAE. THISTLE FAMILY. 



Herbs or shrubs, in the tropics sometimes trees. Leaves various, without 

 stipules. Flowers aggregate in heads, inserted on a common receptacle and 

 surrounded by an involucre of distinct or partly united bracts, in one or 

 several series, the disk-flowers in the center, (i. e., all except those of the 

 marginal series) or all flowers hermaphrodite or by the abortion of the pistil 

 staminate, very rarely pistillate, the ray-flowers or marginal flowers pistil- 

 late or neutral. Plants sometimes dioecious or monoecious. Calyx re- 

 duced to a pappus consisting of bristles, awns, scales, or a cup-like crown, or 

 wanting. Corolla of the disk flowers usually tubular or trumpet-shaped, 

 5- (rarely 4-) lobed or -toothed; that of the ray-flowers usually with a limb 

 cleft on one side and drawn out into strap-shaped or oblong, usually 3-5- 

 toothed ligule. When the ray-flowers are present, the head is said to be 

 radiate, or when they are wanting, discoid. Androecium of 5 stamens; 

 filaments more or less adnate to the corolla-tube; anthers more or less united 

 into a ring (syngenecious) ; except in Kuhnia. Gynoecium 2-carpellary, 

 but with a single ovule and seed ; style single ; branches in of the fertile flowers 

 2, often appendaged. Fruit an achene. Endosperm wanting. [COMPOSITAE.] 



Anther-sacs not tailed at the base. 



Stigmatic lines at the base of the style-branches or below the middle; heads always 



discoid, never yellow or brown. 



Style-branches filiform or subulate, hispidulous. Tribe 1. VERNONIEAE. 

 Style-branches more or less clavate, papillose-puberulent. 



Tribe 2. EUPATORIEAE. 



Stigmatic lines extending to the tips of the style-branches or to the appendage thereof, 

 if present; heads most commonly radiate and with yellow or brown disk-flow- 

 ers. 



Style-branches of the perfect flowers with more or less distinct appendages, these 

 usually strongly hairy outside, glabrous inside, but never with a ring of longer 

 hairs. Tribe 3. ASTEREAE. 



Style-branches of the perfect flowers without appendages, or if with appendages, 



these hairy on both sides and with a ring of longer hairs. 

 Pappus never capillary; style-branches rarely appendaged. 

 Bracts of the involucres herbaceous or foliaceous. 



Receptacle with chaffy paleae subtending the flowers. 



Tribe 6. HELIANTHEAE. 

 Receptacle naked, or in Gaillardia and in some species of Chaenactis 



with bristles; but not chaffy bracted. 



Plant-tissues without oil glands. Tribe 7. HELENIEAE. 

 Plant-tissues, especially the leaves and the bracts with oil-tubes; 



plants therefore heavy-scented. Tribe 8. TAGETEAE. 

 Bracts of the involucres dry and scarious. Tribe 9. ANTHEMIDEAE. 

 Pappus capillary; style-branches often appendaged. 



Tribe 10. SENECIONEAE. 

 \nther-sacs caudate at the base; heads never radiate and corollas yellow only in a few 



species of Cirsium. 

 Anthers not appendaged at the top; heads heterogamous or dioecious. 



Pistillate flowers with filiform corollas. Tribe 4. GNAPHALIEAE. 



Pistillate flowers with tubular-ampliate corollas. Tribe 5. ADENOCAULEAE. 

 Anther with elongated cartilaginous, mostly caudate appendages at the top; flowers 

 all hermaphrodite or the marginal neutral; corolla not filiform. 



Tribe 11. CYNAREAE. 



Tribe 1. VERNONIEAE. 

 One genus. 1. VERNONIA. 



Tribe 2. EUPATORIEAE. 



Achenes 5-angled without intervening ribs. 



Pappus double of 2-12 capillary bristles and as many or fewer outer short thin scales- 



2. HOFFMEISTERIA. 



Pappus of wholly capillary bristles, mostly uniserial. 3. EUPATORIUM. 



Achenes 8-20-ribbed or 8-20-striate. 



Bracts of the involucre herbaceous or partly colored, not striate. 



6. LACINIARIA. 

 Bracts of the involucres not herbaceous, striate-nerved. 



Pappus-bristles plumose ; anthers distinct ; bracts few. 5. KUHNIA. 



Pappus-bristles scabrous or barbellate; anthers united; bracts usually many. 



4. COLEOSANTHUS. 



