316 BOTANICAL GAZETTE [APRIL 
NOTES FOR STUDENTS. 
THE MUCH-STUDIED glandular hairs of Difsacus sylvestris have been 
again examined by Rostock,?? who finds no absorption of food materials, as F. 
Darwin suggested, and no absorption of the water itself, which is purely a 
protection to the leaves against snails and caterpillars. — os 
SOMEWHAT IVE STUDY of Fegatel/a conica,by F. Cavers seems 
to indicate that in large measure it repeats the well-known history of Mar- 
chantia. Contrasting features are the simple air pores, the more differen- 
tiated thallus, the “mycorhizal zone,” the larger sperms, and the fact that the 
cover-cell of the archegonium does not contribute to its elongation (which 
may be true also of Marchantia).— J. M. C. 
RICHARDS AND MACDouGAL™ find that when the nitrogen of the air is 
replaced by CO or by illuminating gas, which contains ca. 40 per cent. of CO, 
seed plants of various kinds show toxic effects, growth, irritability, and chloro- 
phyll formation being notably retarded or inhibited. Mosses were less 
affected, some enduring CO or “gas” for three months, with injury only to 
older leaves, In “gas” there are evidently present other toxic agents than 
G B. 
TONDERA finds® in the young internodes of the Cucurbitaceae the 
“‘starch-sheath”’ supplied with fine-grained starch, equally distributed through 
the protoplasm; whereas only in the older internodes which are not geottopie 
are there coarse grains that lie on the lower side of the cell. This, he 
argues, militates against the statolith theory of geotropism. He thinks the 
“starch-sheath” a storage region during the formation of the zone of 
mechanical tissue (stereome or collenchyma) which adjoins it.—C. R. B. 
RAUNKLER * has arranged the species of Potamogeton into groups based 
mainly upon anatomical characters, such as the build of the central cylinder, 
presence or absence of cortical strands,nature of theendodermis. The author 
considers that anatomical distinctions are more satisfactory than any others in 
recognizing the different species. He claims to settle on anatomical grounds 
the vexed question as to what constitutes P. uzfans Roth, and concludes that 
two quite different plants have been included under this name.—M. A. 
CHRYSLER. 
* Rostock, R., Ueber die biolo 
sylvestris, Bot. Zeitung 622: 11-20 
3CAVERS, F., On 
18 : 87-120, pls. 6-7. 190 
gische Bedeutung der Driisenhaare von Dipsacus 
1904. 
the structure and biology of Fegatella conica. Ann. Botany 
4. 
** RICHARDS, H. M., and MacDoueat, D. T., The influence of carbon monoxid 
and other gases upon plants. Bull. Torr. Bot. Club 31: 57-66. 1904. 
TonDERA, F., Contribution a la connaissance de la gaine d’amidon. Bull. Acad. 
Sci. Cracovie, Math. Nat. Cl. 1903: 512- 
f. 
“Ran C., Anatomical Potamogeton-studies and Potamogeton fluitans. 
Botanisk Tidsskrift 25 : 253-280. 1903. 
