642 



MUSCI OB EKYACE^. 



the peristome and the edge of the theca an elastic ring or annulus is 

 formed ; and occasionally a horizontal septum or epiphragm (pgay/ia, 

 a partition), extends across the mouth of the theca. The setae are 

 sometimes twisted, and so are the teeth of the peristome. The spore 

 of mosses when germinating forms a confervoid prothaUus, from which 

 a leafy axis arises bearing antheridia and archegonia, from the latter 



Fig. 886. 



Fig. 886. 



Fig. 887. ] 



Fig. 8SS. 



of which, after fertilisation, the sporangiferous axis proceeds (figs. 494- 

 496, p. 277). — Mosses are either erect or creeping, terrestrial or 

 aquatic plants, found in aU moist countries, extending from the arctic 

 to the. antarctic regions. They abound most in temperate climates. 

 Spruce met with few mosses in the Amazon and Eio Negro districts. 

 He did not find Funaria hygrometrica there, although it is a very 

 generally distributed moss. They are among the first plants which 



Figs. 885-888. Figures to iUustrate the natural order Musci. Fig. 885. Funaria hygro- 

 metrica slightly magnified. /, Leaves, those connected with the seta lieing caUed peri- 

 chEetial. u, Um-lilce theca, sporangium or spore-case supported on a long twisted stalk 

 or seta, p. c, Calyptra, which exists on one of the thecse, and has fallen from the other. 

 0, Operculum or lid. Fig. 886. Theca of Encalypta vulgaris, -ti, Theca or spore-case, 

 c, Mitriform entire calyptra. o, Operculum or lid. s, Top of the seta. The calyptra is 

 transparent, and the operculum and theca are seen through it. Fig. 887. The same 

 theca, u, with the calyptra removed, o. Operculum detached, showing the peristome, p, 

 with its sixteen cilia or teeth. Fig. 888. Very young theca of Splachnum cut longi- 

 tudinaUy. a. Apophysis or swelling of the seta at the base of the theca. c. Central colu- 

 mella, s. Cavity or bag between the columella and the walls of the theca, containing spores. 

 The integument of the theca is formed of different cellular layers ; the first, e, forms the 

 epidermis, and is thickened at the summit to form thB operculum ; there are then two 

 intermediate layers, which ultimately form the teeth of the peristome ; and lastly, an inner 

 infegament, s, which forms the parietes of the spore-bearing cavity. 



