CAKDUACEAE 1187 



1. Isocoma Drummdndii ( T. & G. ) Greene. Stems branched at the base, 2-3 dm. 

 tall, corymbose above. Leaves numerous ; blades linear x>r slightly broadened upward, 2-5 

 cm. long, entire or nearly so : heads rather conspicuous : involucres campanulate or tur- 

 binate-campanulate, 8-9 mm. high ; bracts narrowly oblong to linear, acute or acutish, 

 with green viscid tips : achenes about 3 mm. long. 



In the lower Rio Grande valley and on the coast of Texas. Spring. 



2. Isocoma coronoplfolia (A. Gray) Greene. Stems 2-6 dm. tall, freely branching 

 and corymbose above. Leaves numerous ; blades 1-3 cm. long, pinnately parted, the seg- 

 ments 3-9, about as broad as the rachis : heads clustered, at the ends of short peduncles : 

 involucres campanulate, 5-6 mm. high ; bracts oblong, linear-oblong or slightly broadened 

 upward, obtuse : achenes about 2 mm. long. 



On plains, Texas. Spring and summer. 



32. ISOFAFFUS T. & G. 



Annual or biennial caulescent herbs, with rough-pubescent foliage. Leaves alternate : 

 blades narrow, often coarsely and remotely toothed, 1 -nerved. Heads radiate, paniculate, 

 peduncled. Involucres many-flowered : bracts narrow, in 2-3 series. Eeceptacle pitted. 

 Kay-flowers 5-12, pistillate. Disk-flowers 7-20, perfect : corollas yellow. Stigmas narrow, 

 pubescent. Achenes terete, broadened upward, pubescent. Pappus a single series of rough 

 nearly equal hair-like bristles. 



Peduncles glandular: bracts of the involucres glandular : ray-flowers 5-8 : disk-flowers 7-14. 



1. I. divaricalus. 

 Peduncles pubescent : bracts of the involucres glabrous : ray-flowers 10-12 : disk-flowers 18-20. 



2. /. Hookerianus. 



1. Isopappus divaricatus (Xutt, ) T. & G. Stems 3-12 dm. tall, hispid and more or 

 less glandular. Leaf -blades linear-oblanceolate to narrowly linear, 2-10 cm. long, acute or 

 acuminate, remotely but sharply toothed, or entire near the top of the stem, copiously 

 ciliate : heads often numerous : involucres oblong-campanulate, 6-6.5 mm. high ; bracts 

 linear-lanceolate to linear, acuminate, glandular-pubescent : ray-flowers with oblong or 

 elliptic-oblong ligules : achenes 2 mm. long, pubescent. 



In dry soil, South Carolina and Kansas, south to Florida and Texas, Summer and fall. 



2. Isopappus Hookerianus T. & G. Stems 3-5 dm. tall, sparingly rough -pubescent. 

 Leaf-blades narrowly linear, sometimes broadest below or above the middle, 2-6 cm. long, 

 acuminate, ciliate near the base, serrulate above the middle, prominently nerved beneath : 

 heads few : involucres campanulate, 5-6 mm. high ; bracts linear-subulate, glabrous or 

 nearly so, firm, sharp-pointed. 



On prairies, Texas. Summer. 



33. MAUCHIA Kuntze. 



Annual caulescent branching herbs. Leaves alternate : blades narrow, entire. Heads 

 radiate. Involucres campanulate, relatively small : bracts thin, gcarious-margined, ap- 

 pressed, abruptly acuminate. Ray-flowers fruit producing, often 12, with short styles. 

 Disk-flowers not fruit producing, about 12, the stigmas filiform. Receptacle flat. Anthers 

 obtuse at the base. Achenes various, those of the ray perfect, thickened upward, 3-angled, ' 

 with a rib at each angle, and pappus of unequal hair-like bristles about as long as the 

 achene ; those of the disk abortive, their pappus usually of 2 bristles, somewhat chaffy, 

 dilated at the base. [Bradburya T. & G., not Raf.] 



1. Mauchia hirt611a (T. & G. ) Kuntze. Foliage hispid. Stems 2-5 dm. tall, slender : 

 leaves various, 1-4 cm. long, those of the basal and lower stem-leaves with narrowly 

 spatulate blades ; upper stem-leaves with blades varying from linear-spatulate to linear-fili- 

 form : heads solitary at the ends of slender branches : involucres 7-9 mm. high ; bracts 

 chaffy, oblong-lanceolate to linear, acuminate, glabrous except the midrib : ligules of the 

 ray-flowers yellow, 6-8 mm. long : achenes 3 mm. long, strigillose. 



On prairies, Texas. Summer. 



34. STANFIELDIA Small. 



Branching caulescent herbs. Leaves alternate, relatively few : blades narrow, rather 

 thick. Heads conspicuous, many-flowered, terminating stout peduncles which are enlarged 

 at the top. Involucre of 3-4 series of loosely imbricated leathery striate-ribbed thin-mar- 

 gined bracts. Disk yellow. Stigmas scarcely flattened, with ovoid appendages. Achenes 

 10-ribbed, the ribs slightly pubescent. Pappus of sordid scabrous bristles. 



