82 BOTANICAL GAZETTE. | April, 
BRIEFER ARTICLES. 
A Plant Heliostat.—The Malva borealis Wall. is a very common weed 
in cultivated g 1 throughout Sout! California. Itis an annual that 
quickly springs up in rich, tilled soil that is atall neglected. This “Malva,” 
as it is appropriately called, is an almost constant stimulus to better cul 
ture, and stands ready to possess the soil, for a time at least, so soon as the 
harrow, gang-plow or hoe ceases to make frequent visits. The large areas 
in walnut groves, orange orchards, open fields for grain growing, and 
even along the roadsides, occupied by this weed, made any observations 
as to its habits an easy task. The most interesting characteristie of this 
mallow,which ti d, is the heliot pi p possessed by the foliage. 
The round-cordate, neatly crenate and more or less five to seven-lobed 
leaves follow the sun during its daily course, and present their upper sur- 
faces to the descending rays. The position of the blades is facing east- 
ward in the morning, and as the day advances the lamin turn to the 
south and become more nearly horizontal. During the afternoon the 
blades approach the vertical position, and at sunset they face the wes*ern 
sky. In short, the malva leaves are living heliostats. This heliotropi¢ 
movement is much more uniform in the leaves of young plants than in © 
those that have grown old and woody. Over an area entirely covered — 
with the malva plants that are about six inches high, and before any flow- _ 
ering stems have begun to shoot upward, the peculiarity of the leaves — 
above noted is strikingly manifest to any person, however blunt his pow- 
ers of observation, when once his attention is called to the matter. 
series of observations was made upon the movement of the leaves 
to determine, if possible, the portion of the blade that is most active in 
the turning, and also to discover the method of the return from the even- 
taken during the day. Inno case was there any indication of any attempt 
to make an entire revolution. The backward movement begins as 8002 
