THISTLE FAMILY 833 



Family 134. CARDUACEAE. Thistle F.vmily. 



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

 i^tipules. 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 pistiUate, 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 usuaUy with a limb 

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

 toothed ligule. When the raj'-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 stjie-branches or below the middle; heads always 

 discoid, never yellow or brown. 

 Style-branches miform or subulate, hispidulous. Tribe 1. \TERNONIEAE. 

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



Tribe 2. EUPATORIEAE. 

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

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

 ers. 

 Style-branches of the perfect flowers wth rnbre 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 m Gaillardia and in some species of Chaenactis 

 with bristles: but not chaffy bracted. 

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

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

 plants therefore heav-v -scented. Tribe S. TAGETEAE. 

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

 Pappus capillar J- ; style-branches often appendaged. 



Tribe 10. SENECIONEAE. 

 Vnther-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 flUform coroUas. Tribe 4. GNAPHALIEAE. 



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

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

 all hermaphrodite or the marginal neutral; coroUa not flliform. 



Tribe 11. CYXAREAE. 



Tribe 1. VERNONIEAE. 

 One genus. 1. Veenonl^. 



Tribe 2. EUPATORIEAE. 



Achenes 5-angled without intervening ribs. 



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



2. HOFFMEISTERL\. 



Pappiis of wholly capillary bristles, mostly uniserial. 3. EuPATORiUii. 



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



Bracts of the Involucre herbaceoiis or partly colored, not striate. 



6. Laciniarlv. 

 Bracts of the involucres not herbaceous, striate-nerved. 



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



Pappus-bristles scabrous or barbeUate; anthers imited; bracts usually many. 



4. COLEOS.\NTHUS. 



