LORQUINIA 29 
frightened. Instead, if the Hzard were alive, he would bite it; or, 
if it were dead, he would take it from my fingers and drag it to 
some place where he would eat it. 
PAUL D. R. RUTHLING, 
Los Angeles. 
THE SEARCH FOR VARIATIONS 
In response to a request for something that would aid a club 
of young naturalists in their observations, I would Hke to suggest 
keeping an eye out for chance variations. The variability of 
organisms is one of their most striking qualities. The members of a 
species are not all cast in the same mold, but an examination of 
many individuals reveals now and again strange and unexpected 
departures from the normal form. These may be in some cases the 
incipient beginnings of a new race, and they occur in both plants and 
animals. These departures are by no means infinitesimal, but they 
may be strikingly different from the parent form. The laciniation of 
leaves or the compounding of their segments are among such vari- 
ations. Alterations in color are perhaps the most frequent, and 
individuals with white flowers occur some time to time in all sorts 
of plants. Their seeds will usually reproduce the new form. 
Variations which breed true in this way — and the large majority 
of these marked departures do come true — are known as mutations. 
As such they have been much written about by biological investi- 
gators in recent years. 
Matters of variation become of particular interest when two 
or more related species occupy the same area. Many such pairs 
of species, as I have called them (On Pairs of Species, Botanical 
Gazette 61:177-212), occur among plants. A very interesting pair 
of this kind is constituted by Adcnostonia faciculatum and A. sparsi- 
foliuin (common greasewood). The latter is much more southerly 
in its distribution, extending down into Mexico. P)Ut on the excur- 
sion from San Diego eastward to the Imperial Valley, following 
the meeting of the Pacific Section of the American Association for 
the Advancement of Science, I recently saw both species growing 
tog:ether over considerable areas. Yet there was no evidence of 
crossing, and little indication of variability in the hurried examina- 
