268 The Botanical Gazette. [July, 
collection in the Columbia College Herbarium fairly repre- 
sents the South American forms. 
The characters that are used in the following synopsis to 
circumscribe sub-groups are by no means absolute, for there 
is always some shading off and overlapping in one particular 
or another, which is forever bound to resist every attempt at 
definite separation. Yet they are natural groups worked out 
from a common origin, and the group characters herein set 
forth can only serve to point out these broader lines of differ- 
entiation along the path of descent. Likewise many of the 
Species approach dangerously near to one another; and the 
complex question of adaptation and modification of adventive 
forms together with the still greater uncertainty which pre- 
vails in regard to hybridization among certain groups of 
or less united at base, or Sree. (AMBLOGYNE. ) 
This section is as well marked in geographical limits as 1n flower 
characters, being restricted with few exceptions to Texas, New Mexico, 
Arizona, Nevada, southern California and the arid plains of northern 
Mexico. The characteristic rank weedy nature of the genus is some- 
what overcome here by a tendency to color and gracefulness of habit. 
* Plants monectous. 
+ Stamens 2 or 3. 
++ Utricle indehiscent. 
«1. A. BERLANDIERI (Moq.). 
Sarratia Berlandieri Mog. DC. Prod. 132: 268. 1849. 
Stem slender, ascending or erect, 15 to 30™ high, ere 
ing from base: leaves crowded, deciduous on the on pee 
of the stem, oblong-obtuse to oblanceolate, 1.5 to 2-5 st 
inflorescence in small clusters, crowded, axillary: pie 
darkish, short (2™"): bracts one-third as long as the Ree 
stamens two: fruiting sepals 3-nerved, coalescent i nike 
third their length, not constricted into a tube above: utr 
