ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 71 



female spores, just as has been previously shown to be the case in some 

 other dioicous plants, namely, in Mure ban tin (by Blakeslee), and in 

 Barbula unguieulata, Brgum argentium and Ceratodon purpureus (by 



El. and Em". Marchal). 



Structure of Mosses in Relation to Habitat.* — A. J. Grout pub- 

 lishes notes upon some relations between the habitats of mosses and 

 their structure. Species that grow upon tree-trunks have erect capsules, 

 so, too, those that grow on the faces of cliffs ; and these erect capsules 

 very rarely have complete double peristomes. The double peristome is 

 a device, for preventing the too rapid escape of spores from pendent 

 capsules. There seems to be some relation between the annual cleisto- 

 carpous mosses and their habitat, moist bare soil. Again, mosses of 

 xerophytic habit have small cells and very thick walls, a further protec- 

 tion against desiccation being sometimes added in the form of large 

 papillae on the surface of the cells. Pleurocarpous mosses that grew 

 on the bark of trees and in similar xerophytic habitats are remark- 

 able for the large number of quadrate thick-walled alar cells in their 

 leaves. On the other hand, the alar cells of aquatic or subaquatic 

 pleurocarpous species tend to become enlarged and inflated, the other 

 leaf-cells being exceedingly long and narrow. The meaning of this 

 modification is obscure. 



Mosses and Environment.! — A. Geheeb publishes a posthumous 

 manuscript by K. Schimper upon the habitats of mosses and the effect 

 of environment upon them. The author considers the manifold in- 

 fluences that affect mosses and lichens, together with the correspond- 

 ing differences effected in their morphology. 



Resting Periods in Riccia.J — E. Zacharias publishes some notes on 

 the periodicity of hepatics. He kept under observation in a greenhouse 

 two species of Eiccia, the common R. nutans and the Algerian R. Gou- 

 getiana. The former he observed to die down in the autumn, only a 

 small portion of the apical margin retaining life and resuming growth 

 in the following spring. R. Gougetiana on the other hand has its 

 resting period in the summer : having formed an apical bud in the spring 

 it died off, and the bud resumed growth in the autumn. 



Abnormal Sporogonia in Mosses. §— I. Gyorffy describes instances 

 of twin or triplet sporogonia. Such abnormalities have previously been 

 recorded for twenty-three mosses. Gyorffy adds Dissodon Froelichianus 

 and Plagiobryum demission to the list, giving figures and descriptions 

 of the freaks. 



Artificial Production of Propagula inBarbula.j]— J.Maheu descri 

 a method for obtaining experimentally the production of propagula with- 

 out failure in several' species of Barbula, in which normally they are 

 entirely absent. Broadly speaking, a specially arranged moist chamber 

 was employed, so as to insure a saturated atmosphere. Some of the 

 experiments were made in the light, others in the dark. 



* Bryologist, xi. (1908) pp. 97-100. 



t Beih. Bot. Centralbl., xxiv. 2te Abt. (1908) pp. 53-66. 



t Verh. Nat. Wiss. Verein, Hamburg, xv. (1908) pp. lxxv-lxxvi. 



§ Magyar Bot Lapok, vii. (1908) pp. 61-74 (pi.). 



|| Bull.' Soc. Bot. France, 1908, pp. 445-53 (2 pis.). 



