140 SUMMARY OF CURRENT RESEARCHES RELATING TO 



a soil free from lime (such as Hylocomium loreum., Hijpnum Schreheri, 

 H. ct/pressiforme, Mnium punctatum, Barhvki subuJafa, Bartramia 

 pomiformis, Bryum argenteuM, Dicranum scopariam and Hedwigia ciliata) 

 germinate in a neutral to weak alkaline solution. In nature, this 

 influence of the reaction on germination determines the distribution of 

 the species. Bogs and damp humus have an acid reaction ; other soils 

 have an alkaline reaction, strongly alkaline in case of the lime-containing 

 rocks. The calcareous contents of the rock do not act as such, but 

 through the presence of OH-ions. The spores of mosses which grow on 

 dry rocks sink to the bottom in water, while those of other mosses float. 

 The species with spores that sink are more adapted for habitation on 

 dry rocks ; when the rocks are wet they remain in the rock crevices, 

 whereas floating spores would be washed off. The possibility of 

 distribution is greater for the spores of species growing in dry places, 

 on account of the greater movement of air prevailing there. The 

 absence of these species in damp habitats is probably caused by the 

 much quicker germination of the mosses that are suited for damp places. 

 The time of ripening of the sporogonium of mosses growing in dry 

 places takes place during the period between the maximum of dampness 

 of soil and that of the maximum of summer rainfall — that is, in spring- 

 time. With increasing dampness of habitat, the time of ripening is 

 more evenly distributed over the different seasons. An attempt was 

 made to increase the speed of the germination of the mosses from dry, 

 sunny habitats by previous warming, but without marked success. A 

 connexion was not firmly proved between a capability of germinating in 

 the dark in an inorganic solution and a particular habitat, but it 

 possibly exists. Cierraination in the dark succeeds more easily in a 

 lesser concentration of inorganic nutritive solution. It was impossil)le 

 to germinate certain species in the dark. Excretions of lime on the 

 leaf -points of mature plants were only noticed on calcifuge species. 



Moss-calyptra with Stomata.* — P. Janzen describes the occurrence 

 of stomata on quite normally formed calyptra of Encalypta ciliata. 

 Stomata are common on the thallus of frondose hepatics, on tlie 

 receptacles of Marchantieffi, and on the sporogonium of Anthoceros ; but 

 are unknown on the foliose hepatics. On the capsules of mosses they are 

 frequent. The stomata of the calyptra of Encalypta ciliata are descril)ed 

 as being structures arrested in development. The author recommends 

 that the calyptras of Funaria, Gampylopus, Trematodon, Grimmia, etc., 

 which, Wke Encalypta, are provided with water-sacks, should be examined 

 for similar stomata. 



Fossombronia crispula in Indiana.f — E. J. Hill gives an account 

 of Fossombronia crispula Austin, with a description of its structure, and 

 of the nature of the habitats in which he has found it in the Dune 

 region of Indiana. It occurs in sloughs from which the water has 

 dried away, especially on the vertical sides of old footmarks left by cows 

 in the drying mud in summer-time. The plant is evidently annual, the 



* Hedwigia, Ivii. (1916) pp. 263-5. See also Bot. Centralbl., cxxxii. (1916) p. 409. 

 t Bryologist, xix. (1916) pp. 67-8. 



