Xerophytic Adaptations, of Bryophytes. 155 
spp. (fruit seldom found in the British Isles), Dicranodontium 
longirostre, Campylostelium saxicola. 
(4) Papillosity. Thickenings of the epidermis so as to form 
protuberances are common in many organs associated with, or 
belonging to the sporophyte. The perianth is tuberculate or 
papillose in Fndlania dilatata (Fig. 2, 16), Cololejeunea Rossettiana, 
Aplozia crenulata var. cristulata, thecalyptra in Polytrichum aloides, 
Pottia asperula, P. Wilsoni, P. recta, Eucalypta vulgaris, etc., and 
the seta in Brachythecium rutabulum (Fig. 1, 9), B, velntinum, 
Buxbaumia and some species of Eurynchium. Wheldon (25) 
throws doubt on the xerophytic character of the papillose seta in 
B. rutabulum, as he could find no relationship between the number 
and size of the papillae to the various habitats of this species, but 
the general occurrence of papillae on the leaves of xerophytes 
implies their xerophytic nature, and my observations on the 
influence of habitat on the length and papillosity of the setae lead 
me to take a different view. It is quite probable that a comparative 
examination would not prove the papillose seta to be a xerophytic 
device, unless other disturbing factors were taken into account. 
In many mosses the exposed peristome is papillose (e.g., Grimmia 
apocarpa) whilst the spore is frequently ornamented with crests, 
ridges, or papillae. Campbell says in regard to hepatics, after 
referring to the excrescences of the spore, “ the exospore is 
especially well developed in species where the spores are exposed 
to great heat or dryness,.in those species that are found in 
cooler and moister situations, the exospore is frequently thin ” (3). 
This papillosity is shown in species of Pottia, Gymnomitrium, 
Cololejeunea, Colurolejeunea, Fossombronia, Scapania, in Lophozia 
alpestris, Lepidozia reptans, etc. 
(5) The bell-shaped calyptra forms a protective bonnet over the 
urn in many species of Eucalypta, (Fig. 1, 6), Funaria, Physcomi- 
trium, Ulota, Orthotrichum. It is hooded or cucullate in Zygodon, 
Neckera, Seligeria, Grimmia crinita, Leptodon Smithii and Leucodon 
sciuroides. 
(6) The Hairy Character of the Calyptra and other protective 
bodies of the sporogonium, the hairs or cilia reducing transpiration 
and retaining water. The calyptra is hairy in Polytrichum, 
Orthotrichum anomalum, O. leiocarpon, Eucalypta ciliata, Leptodon 
Smithii, etc.; the perianth is ciliate in Chandonanthus setiformis, 
Lepidozia setacea, Lophozia guttulata, and the perichsetial leaves or 
bracts are finely pointed or ciliated in some xerophytic species of 
