Contributions to Western Botany. 35 
about 125 species, chiefly confined to tropical America; in our 
region there are a few species found as high as the Lower Tem- 
perate or Juniper Zone and are found only in arid places, exposed 
to the direct rays of the sun, and blooming till the close of the 
season, 
SYNOPSIS OF GHNERA. 
A. Flowers not collected into a head, except some species of 
Beerhavia; involucre not evident, the bracts, if present, 
eing separate, small and situated on the pedicel, or 
apparently at its base. 
1. SELINOCARPUS. Fruit with 3-5 prominent, thin wings. 
2. BCZRHAVIA, Fruit 3- 10-ribbed, the ribs enlarged upwards, except in 
B. annulata and tea ag ascens, toward the summit, Plants blooming 
throughout the seas 
3. ACLEISANTHES. Fruit 5- 15-ribbed, truncate at both ends, ribs 
sually not enlarged above; calyx tube filiform, not angled, 1 or 
more inches long; flowers mostly single, veer sessile; stamens 2-5; 
leaves acute at base and short-petioled it 
2A. Flowers in heads. 
2AB. Flowers surrounded by numerous and distinct bracts, 
leaves thick and leathery. 
4. SORONIS: races i in a whorl at the base of the flower Cluster, 

or winged, at least at tip. 
5. HERMIDIUM. Bracts leaf-like, not at the base of the flower cluster 
t each attached to the pedicel of a flower, and all densely aggre- 
gated, very large, green orcolored and leathery; flowers funnel-form: 
bell-shaped; fruit globular and smooth, not lobed nor winged; 
perennials. 
2A2B. Bracts united into a cup, at least at very base. 
2A2BC. Fruit not winged nor tubercled on the angles; invo- 
lucre 3-5-lobed; tufted perennials. 
6. MIRABILIS. Involucre neither membranous nor enlarged in fruit. 
6 Gas ttiae Involucre te Marga enlarged and membranous in 
fruit; stamens long-exsert 
