1 5 7 
Xerophytic Adaptations of Bryophytes. 
the furrows ( e.g ., species of Orthotrichum and Ulota ), and the 
guard-cells may he sunk below thecuticular cells as in 0. anotnalum 
(Fig. 1, 11) and O. cupulatum. In Polytrichum piliferum and its 
allies the stomata are found in the deep constriction between the 
apophysis and urn. 
(8) Plication of the Capsule or the organs surrouuding it, by 
means of which the assimilatory or protective surface is increased 
without a corresponding expansion of the exposed area. The 
calyptra is plicated in Coscviodon cribrosus, species of Orthotrichum, 
Ulota crispa, etc., the perichsetial leaves in Tortula ruraliformis, 
and the perianth in Chandonanthus setiformis, and Anastrepta 
orcadensis. Striae are often present in many xerophytic mosses 
(species of Ceratodon, Orthotrichum, Encalypta, Cynodontium, etc.) 
and these may partially serve a similar purpose, though the 
grooving is often only slightly evident before the maturity of the 
spores. In most cases the striae are longitudinal but in some cases 
they are spiral, as in Encalypta streptocarpa. 
(9) Fleshy or bulbous involucre. In Alicularia Breidleri and 
A. Geoscyphus (Fig. 2, 17) the involucral base of the sporogonium 
forms a fleshy root-like body from which rhizoids penetrate into the 
soil. This “root” is really formed from the gametophytic tissue 
and forms a storehouse of food and moisture from which the foot 
of the sporogonium may draw its nourishment. That it is a 
xerophytic device is evident since it is absent or poorly developed 
in the moist or shady ground form (var. suberecta) of A. Geoscyphus 
In some plants, which can scarcely he considered as xerophytes, the 
involucre has extended still more, so that it forms a hollow tube 
(perigynium or marsupium) which is pendulous and more or less 
subterranean. This pendulous perigynium is found in Geocalyx, 
Saccogyna, and Calypogeia (Fig. 2, 18) in all of which a perianth is 
absent. 
In the somewhat hydrophytic Riccia Jluitans, the capsule is 
enclosed in a spherical protuberance on the ventral side of the 
thallus and is furnished with rhizoids on the enclosing tissue. 
III. Protective Arrangements in the Gametophyte. 
The tissues are usually less resistant in the gametophyte than 
in the sporogonium, and the former has a longer life, so that some 
protection is necessary to ensure it against drying up. When 
water is present, it is quickly absorbed, and afterwards distributed 
to the various parts of the plant according to their requirements. 
