80 BOTANICAL GAZETTE [JANUARY 
The vegetation of California—CANNON* has published the address on the 
vegetation of California in relation to environment, which he delivered in 
1913, at Carmel, California, before the members of the International Phyto- 
geographic Excursion. The California environment is highly peers 
owing to the great climatic diversity, which in turn is associated with phy: 
graphic complexity. The corresponding specialization of the vonanien is 
shown in the marked vegetational types and also in the large display of endem- 
ism. An example of another sort of specialization is brought out in a considera- 
tion of the root relations of the oaks.—H. C. Cow Les. 
Branching of Rhizophora roots.—The repeated branching of the prop 
roots of Rhizophora is well known and has often been described. DocTERS 
vAN LEEUWEN has made the remarkable discovery that this branching 
is not a fixed feature of the roots, but is caused by an unidentified Scolytid 
beetle, which eats the growing portion of the roots. The destruction of a 
growing root tip is followed by the appearance of a lateral branch, about a 
centimeter above the killed portion. One plant was found far from the sea, 
in which an uninjured root grew down to the ground without branching.— 
H. C. Cow es. . 
Bees and cotton blossoms.—Stimulated by the anendeat views as to the 
office of flower color in the attraction of insects to flowers, H. A. ALLARD® has 
made a series of observations on the visitation of cotton blossoms by bees, 
especially by Melissodes. It is concluded that the showiness of the flowers is 
the chief factor determining the insect visits. ‘The removal or covering of the 
petals greatly reduces the number of visits. Only 12 per cent of the flowers 
inspected by bees were actually entered by them. Evidence is given of the 
influence of associative memory.—H. C. CowLEs 
Polyporaceae of Ohio.—OveERHOLTS’’ has published a monograph on the 
Polyporaceae of Ohio, with full descriptions and keys. Approximately 10° 
species are described, representing 10 genera. One of the features of the 
monograph is that the descriptions are exactly comparable with one another, so 
that the contrasting characters are brought out with unusual clearness.— 
J. MAC 
54 CANNON, W. A., Specialization in vegetation and in environment in California. 
Plant World 17: 223-237. figs. 3. 1914. 
8s DocTERS VAN LEEUWEN, W., Uber die Ursache der wiederholten Verzweigung 
der Stiitzwurzeln von Rhizophora. Ber. Deutsch. Bot. Gesells. 29:476-478. /igs- 2- 
IQIT. 
® ALLARD, H. A., Some experimental observations concerning the behavior of 
various bees in their visits to cotton blossoms. Amer. Naturalist 45:607-622, ne 
685. Igri. 
7 OvERHOLTS, L. O., The Polyporaceae of Ohio. Ann. Mo, Bot. Garden 1:81-155- 
Igt4. é 
