39. Flaveria Juss, 



Glabrous or puberulent herbs, usually annual; leaves opposite, narrow, entire 

 to dentate, sessile, often more or less connate; heads numerous, sessile or short- 

 pedunculate, in dense glomerules or cymelike clusters; involucre usually narrowly 

 campanulate to nearly cylindric; phyllaries 1 to 8 subequal and often 1 or 2 

 smaller outer ones; receptacle small, naked or setose; ray flowers solitary, pistillate 

 and fertile or absent; rays entire, emarginate or 3-dentate terminally, yellow, in- 

 conspicuous; disk flowers 1 to 15, perfect, fertile; corolla yellow, 5-toothed 

 terminally; style 2-parted, reflexed, obtuse; achenes oblong, somewhat compressed, 

 10-ribbed; pappus absent or in F. chloraefolia present and of 2 to 4 distinct 

 irregular scales. 



A genus of about 20 species in the warmer parts of America. 



1. Pappus of 2 to 4 scales; leaves connate-perfoliate, broad; throat of the disk 

 corollas elongate, funnelform 1. F. chloraefolia. 



1. Pappus absent; leaves barely connate (2) 



2(1). Phyllaries 3, rarely 4 2. F. campestris. 



2. Phyllaries 5 to 7 3. F. op positi folia. 



1. Flaveria chloraefolia Gray. Fig. 776. 



Herb to 2 m. tall, the herbage glaucous; leaves ovate-oblong to lanceolate, 

 25-100 mm. long, 10-35 mm. broad, glabrous, connate-perfoliate; heads in open 

 cymose clusters, 11- to 13-flowered; phyllaries 5, oblong, 6-7 mm. long, the 

 outer calyculate ones 2, lanceolate; receptacle naked; ray flower absent; disk 

 corolla 6 mm. long, glabrous; achenes 3 mm. long; pappus of 2 to 4 hyaline 

 unequal incurved scales, the larger about 0.5 mm. long. 



Infrequent to rare in mud along creeks in calcareous or alkaline areas in the 

 Tex. Trans-Pecos, rare to w. part of Edwards Plateau, and N.M. (Chaves and 

 Guadalupe cos.), late summer-fall; Tex. to N.M., Dgo. and N.L. 



2. Flaveria campestris J. R. Johnst. 



Taprooted annual, the erect stems glabrous or pubescent only at the nodes; 

 leaves linear or linear-lanceolate, serrulate, 3-ribbed, narrowed basally, slightly 

 connate, 25-70 mm. long, 10-25 mm. broad; heads 4- or 5-flowered; phyllaries 3, 

 nearly equal, 5 mm. long, the outer shorter ones 2 and unequal, 1-3 mm. long, 

 linear-lanceolate; receptacle naked; ray oval, reflexed, 2.5 mm. long; disk flowers 



3 or 4; corollas 3 mm. long; achene 2.5-3 mm. long, that of the ray slightly 

 larger than the rest; pappus absent. 



Frequent in low waste ground or disturbed ground, in alkali flats, low moist 

 or wet prairies, in alluvial thickets along streams, and in seepage areas and about 

 ponds, in w. half of Okla. {Waterfall), the Tex. Plains Country and N.M. 

 (Valencia Co.), late summer-fall; Mo. to Colo., N.M. and Tex. 



3. Flaveria oppositifolia (DC.) Rydb. 



Taprooted annual 3-10 dm. tall, simple below; leaves glabrous, broadest at 

 the sessile base, nearly linear, entire or rarely spinulose-denticulate; heads of 10 

 to 15 flowers in ample rather open cymose clusters; phyllaries 5 to 7, oblong, 



4 mm. long; receptacle naked; ray flower absent; disk corolla 3 mm. long, 

 glabrous; achenes 1.5 mm. long; pappus absent. 



Locally abundant in poorly drained or marshy coastal areas, Rio Grande Plains 

 and s. part of s.e. Tex., late summer-fall; Tex., Tarn., N.L., Coah., Ver. and 

 perhaps elsewhere in Mex. 



1683 



