428 The American Naturalist. [May, 
In Europe it occurs from Spain to France, Belgium, Holland, Great 
Britain, Ireland, Denmark, Norway and Sweden, and along the Med- 
iterranean coast of France, Italy, Greece and Turkey. Even the 
sandy tracts of interior countries are not free from it ; thus it is found 
in Germany, Austria, Hungary and Russia. It occurs also in temper- 
ate Asia. In America as stated above, it extends from New England 
to Georgia. The variety is apparently much less widely distributed, 
but the exact limits of its geographical range are not well defined, 
most recent authors not regarding it as sufficiently distinet to warrant 
separate treatment. 
The technical description of the variety (to which alone the name 
Russian Thistle is applied) as drawn up by L. H. Dewey of the United 
States Department of Agriculture, is as follows: 
“ Salsola kali L. var. tragus DC. Prod. XIII, 2, 187 (1849). Her- 
baceous, annual, diffusely branching from the base, usually densely 
bushy at maturity, .5 to 1 m. high and twice as broad, smooth ot 
slightly hispid ; root simple, dull white, slightly twisted near the apes 
leaves alternate, sessile; of the young plant deciduous, succulent, linear ; 
or subterete, 3 to 6 cm. long, spiny-pointed, and with narrow, denticu- 
late, membranaceous margins near the base; leaves of mature plant 
peristent, each subtending two leaf-like bracts and a flower, at intervals 
of 2 to 10 mm, rigid, narrowly ovate, often denticulate near the base, 
spiny-pointed, usually striped with red like the branches, 6 to 10 mm. 
long; bracts divergent, like the leaves in size and in all respects but 
position ; flowers solitary and sessile, perfect, apetalous, about 10 mm. 
in diameter ; calyx membranaceous, persistent, enclosing the depressed 
fruit, usually rose colored, gamosepalous, cleft nearly to the base Into 
five unequal divisions about 4 mm. long, the upper one broadest, the 
two next the subtending leaf next in size and the lateral ones narro™ 
each with a beak-like, connivent apex, and bearing midway 0n she 
back a membranaceous, striate, erose-margined wing about 3 mm. longs 
the upper and two lower ones much broader than the lateral ones; 
stamens 5, about equalling the calyx lobes; pistil simple ; styles 2,8 in 
der, about 1 mm. long; seed 1, obconical, depressed, abou eo 
iameter, dull gray or green, exalbuminous, the thin seed-coat close 7 
covering the spirally-coiled embryo; embryo about 12 mm. long © 
2 terete cotyledons.” i 
Salsola is one of the prominent genera of the family Chenopodiace®, 
and is the most important member of the tribe Salsolew. Its tag 
ma 31, Agricultural Experiment Station of the University of Nebraske oe 
