1911] CURRENT LITERATURE 495 
of their environment. In short, it is a study of the ecological anatomy of 
fossil leaves. The leaves of Calamites are mostly known as impressions, and 
Tuomas has referred the structures he has been able to obtain to the better 
known impression forms. The petrified material used was obtained from the 
Lower Coal-measures (Halifax Hard Bed), and five types of leaf were distin- 
guished. The twigs bearing the leaves proved to be quite interesting in stelar 
structure, especially in its relation to that of young stems of Equisetum. 
The ecological conclusion is as follows: ‘The leafy twigs seem to have 
grown in a pendulous fashion, and the structure of the mesophyll and epidermis 
suggests that the habitat was a damp one. On the other hand, the leaves 
possess some xeromorphic features, such as the presence of fibers in the longer 
forms. The evidence points to a marsh or swamp forest as their habitat; 
this may Sali been near the sates but if so the soil probably contained little 
salt.”—J. M 
Transpiration in salt marsh plants.—Transpiration rates of cut shoots of 
Salicornia annua and Suaeda maritima have been found by DELF* to be equal 
to or greater than those from equal surface areas of such mesophtyes as Vicia 
Faba. The highest degree of succulence seemed to be accompanied by the 
highest transpiration rate per unit area. Relating transpiration to evaporation 
from a water surface, unit areas of Salicornia lost 32 per cent and of Vicia 
26 per cent as much water as equal areas of water surface. It was shown that : 
Salicornia is able to absorb water readily through the surface of its stems when 
submerged, and less convincingly that it does not absorb sufficiently through 
its root system to replace the loss by transpiration except in a humid atmos- 
phere. This seems the more surprising, since TRANSEAU* has shown evapora- 
tion to be exceptionally high in salt marshes. The stomata in Salicornia 
and Aster trifolium appear to have distinct powers of movement in young 
plants early in the season, losing this plasticity at a later date——Gro. D. 
ULLER 
Cytology of the ascus.—An account of the cytology of Helvella crispa Fries 
is given by Miss CarruTuers.s The cells of the hypothecium are one to 
several-nucleate, and some of the nuclei were observed to fuse in pairs, but no 
migration was observed like that in Humaria. An attempt was made to deter- 
mine the number of chromosomes on the spindles in the vegetative hyphae. 
Apparently two chromosomes are present in the vegetative spindles, and four 
or eight on the spindles in the fertile hyphae, but owing to the minuteness of 
the objects not much importance can be attached to these observations. The 
43 Deir, E. Marion, Transpiration and behavior of stomata in halophytes. Ann. 
Botany 25:484—505. Igtt. 
4 Bor. Gaz. 45:217-231. 1908. 
45 CARRUTHERS, D., Contributions to the cytology of Helvella crispa Fries. Ann. 
Botany 25:243-252. ais. 2. 168%, 
