BRY0PH7TA. 217 



dens, Polytricliuin, including the well-known Hair-cap 

 Moss (P. commune), Timmia, Bryum (Figs. 126, (rand H), 

 Mnium, Funaria (P. hygrometrica, Pigs. 125, 136, A to F, 

 and 137); Fontinalis, large floating mosses, common in 

 brooks and rivulets; Cylindrotheciiim ; Olimacium (0. 

 americanum is a large tree-shaped moss) ; Hypnum, the 

 bog-mosses, etc. 



Practical Studies. — [a) Collect several kinds of mosses in fruit ; 

 some of these should be of large species. Note the brownish root- 

 hairs, the stem and leaves, the spore-fruit composed of a slender 

 stalk bearing a spore-case, the latter in some species covered by a 

 membranous or hairy cap (calyptra). 



(6) Select a broad-leaved species. Mount a single leaf in water, 

 and examine with a low power. Note that the leaf is (generally) a 

 single layer of cells, and that the midrib (if present) is composed of 

 elongated cells. Make cross and longitudinal sections of stems of the 

 larger species, and note that some of the cells are elongated and fibre- 

 like. 



(c) Place a spore-case under the microscope and examine with a 

 low power, noting the lid (Fig. l'J6, O). Now remove the lid and 

 observe the teeth (Fig. 136, H). The teeth may be studied still 

 better by splitting the spore-case from base to apex and then mount- 

 ing in alcohol, and afterward adding potassic hydrate. In this 

 specimen spores may be studied also. 



id) Split a young spore-case and examine the external surface of 

 the lower part for breathing-pores. 



(«) Collect a number of mosses not in fruit, showing at the apex 

 of their stems little cup-shaped whorls of leaves. Make several 

 vertical sections of one of these cups, and mount in water. Examine 

 for antherids and archegones (Figs. 125 and 126). Antherozoids 

 may sometimes be seen with a high power. 



(/) The first stage (protonema) of a moss may be found by scrap- 

 ing off some of the greenish growth from a wall or cliflE where young 

 mosses are just springing up. By mounting some of this in water 

 and washing away the dirt the branching green growth may generally 

 be seen. (Fig. 127.) 



Systematic Literature. — Lesquereux and James, Manual of the 

 Mosses of North America 



