456 FLORA OF TEXAS. 



ciduous ; stamens 1-several, hypogynous ; anthers 2-celled, 

 roundish; ovule erect; style simple; stigma simple or 

 branched; achenium inclosed in the indurated, mostly 

 ribbed, often glanduhxr base of the calyx ; embryo coiled or 

 folded around copious mealy albumen; cotyledons leafy; 

 radicle inferior. 



SYNOPSIS. 

 * Flowers surrounded by a calyx-like involucre. 



Involucre open^ membranaceous, o-lobed. Herbs Oxtbaphtb. 



** Flowers without an involucre. 

 * Flowers perfect. Embryo coiled. Herbs Boerhaatia. 



OXYBAPHUS, Vahl. 



Flowers perfect, 1-5 in a cluster, surrounded by an open 

 cup-shaped 5-lobed involucre; calyx-tuhe very short, the 

 bell-shaped limb 5-lobed, deciduous ; stamens 3, exserted ; 

 style slender; stigma capitate; achenium inclosed in the 

 indurated ribbed persistent base of the calyx. — Erect herhs, 

 from thick perennial roots; leaves opposite; flowers ter- 

 minal, purple or rose-color. 



0. Ais^GUSTiFOLius, Sweet. Stem smoothish, branching 

 above; leaves linear-lanceolate, smooth, obtuse at the ses- 

 sile base, the upper ones distant, acute; floiuers loosely 

 panicled; involucre with rounded hairy lobes, at length 

 enlarged and strongly nerved, 3-flowered ; base of the calyx 

 villous. Stem 3°-4'' high; leaves 2' long; calyx 4"-5" 

 long, whitish, veiny. 



0. KYCTAGIXEUS, Swect. Nearly smooth, erect, with 

 alternate or forked Iraiiches ; leaves broadly ovate or ob- 

 long, subcordate, acute; 'peduncles solitary, axillary and 

 terminal; involucre pubescent, 3-5-flowered; xterennial. 

 Ked River. — il/rt?T^. 



0. cocciNEUS. Roots ligneous, black and tortuous ; st&nis 



