COMPOSITAE. 



VOL. III. 



4. Parthenium hispidum Raf . Creeping 

 or Hairy Parthenium. Fig. 4435. 



Parthenium hispidum Raf. New Fl. N. A. 2 : 35. 

 1836. 



P. repens Eggert, Cat. PI. St. Louis 16. 1891. 



Similar to the two preceding species, but 

 lower, seldom over 2 high. Rootstocks slen- 

 der, forming runners ; stem pilose or hispid 

 with spreading hairs; leaves hispid on both 

 sides, irregularly crenate, sometimes lyrate at 

 the base, the teeth rounded and obtuse; heads 

 fewer, slightly larger, in a small loose corymb; 

 outer bracts of the involucre proportionately 

 broader. 



Barren rocky soil, Missouri to Kansas and 

 Texas. April-July. 



56. CRASSINA Scepin, Sched. Acido Veg. 42. 1758. 

 [ZINNIA L. Syst. Ed. 10, 1221. 1759.] 



Annual or perennal herbs, some species shrubby, with opposite, entire, or sparingly ser- 

 rate, mostly narrow and sessile leaves, and large or middle-sized heads of both tubular and 

 radiate flowers. Ray-flowers pistillate, yellow, or variegated, persistent on the achene. Disk- 

 flowers perfect, fertile; corolla cylindraceous, its lobes villous. Involucre campanulate to 

 nearly cylindric, its bracts obtuse, dry, firm, appressed, imbricated in 3 series or more, the 

 outer gradually shorter. Receptacle conic or cylindric, chaffy, the chaff subtending and 

 enwrapping the disk-flowers. Style-branches elongated, not appendages. Achenes of the 

 ray-flowers somewhat 3-angled, those of the disk flattened. Pappus of few awns or teeth. 

 [In honor, of Paul Crassus, an Italian botanist of the sixteenth century.] 



About 12 species, natives of the United States and Mexico. Type species : Chrysogonum peru- 

 vianum L. 



i. Crassina grandiflora (Nutt.) Kuntze. 

 Prairie Zinnia. Fig. 4436. 



Zinnia grandiflora Nutt. Trans. Am. Phil. Soc. (II) 

 7: 348. 1841. 



Crassina grandiflora Kuntze, Rev. Gen. PI. 331. 1891. 



Perennial, woody at the base, tufted, much 

 branched, rough, 4'-6' high. Leaves rather rigid, 

 linear to linear-lanceolate, entire, 6"-i5" long, 

 li" wide, or less, connate at the base, acute or 

 acutish, crowded; heads numerous, peduncled, 

 terminating the branches, io"-i8" broad; rays 4 

 or 5, broad, yellow, rounded, or emarginate, their 

 achenes with a pappus of 2 or 4 awns ; involucre 

 campanulate-cylindric, 3"-4" high; style-branches 

 of the disk flowers subulate. 



In dry soil, Kansas and Colorado to Texas, Mexico 

 and Arizona. June-Sept. 



57. HELIOPSIS Pers. Syn. 2 : 473. 1807. 



Perennial herbs (a tropical species annual), with opposite petioled 3-ribbed leaves, and 

 large peduncled terminal and axillary heads of tubular and radiate yellow flowers. Invo- 

 lucre hemispheric or broadly campanulate, its bracts oblong or lanceolate, imbricated in 2 

 or 3 series. Receptacle convex or conic, chaffy, the chaff enveloping the disk-flowers. Ray- 

 flowers pistillate, fertile, the rays spreading, the tube very short, commonly persistent on 

 the achene. Disk-flowers perfect, the tube short, the limb elongated, 5-toothed. Anthers 



