W. Watson. 
156 
mosses and liverworts, e.g., Seligeria acutifolia, Chandonanthus 
setiformis. The hairy vaginulae of such mosses as Orthotrichum 
stramineum and Leptodon Smithii serve a similar purpose. 
(7) The Position of the Stomata. When these are present, they 
are arranged in places where they are more or less shaded. In the 
smooth urns they are confined to the base of the capsule (e.g. f 
Orthotrichum leiocarpum) ; in the grooved urns they are hidden in 
Fig. 2. Xerophytic Adaptations in Liverworts. 1 , Lepidozia reptans, showing 
the leaves with incurved lobes, and two of the flagella, X 20 ; 2, Lejeunea 
cavifolia, shoot with water sacs and under-leaves, X 30 ; 3, stem and two leaves 
of Lopliozia atlantica, showing the inturned apics of the three-lobed and concave 
leaf, X 10 ; 4, Cololejeunea Rossettiana, with papillose leaf, X 25 ; 5, stem and 
leaf of Lophocolea cuspidata, x 10; 6, ciliate leaf of Ptilidium pulcherrimum, x 10; 
7, stem and two leaves of heath form of Gymnocolea inflata, x 10 ; 8, Scapania 
nndulata, normal leaf, x 10; 9, S. nndulata, leaf with diverging lobes, x 10; 
10, Frullania dilatata, under surface showing water-sacs, x 10 ; 11, leaf-cells of 
Chiloscyphus polyanthus var. fragilis, a liverwort of wet places, x 200; 12, leaf- 
cells of Alicularia Breidleri with thick cell-walls, x 200 ; 13, leaf-cells of Gymno- 
mitrium adustum, a liverwort of sub-alpine rocks, x 200; 14, leaf-cells of 
Bazzania Pearsoni, with very large trigones, x 200; 15, perianth of Cephalozia 
media, x 10; 16, F. dilatata, perianth with ridge and tubercles (position of 
sporogonium indicated by dotted lines), x 10; 17, bulbous involucre (B.) and 
perianth [per.) of Alicularia Gcoscyphus, x 5; 18, marsupium (mars.) and sporo¬ 
gonium of Calypogeia Trichomanis, x 3 (s., seta; c., capsule valves). 
