; I N MUSCTNE.W. 



secondary prolonema may, however, be formed from any root-hair when exposed 

 to light in a moist atmosphere. It is not known whether, under such circum- 

 stances, the apical cell of the stouter rhizoids can itself undergo the change ; but 

 it is certain that the separate cells of the root-hairs form branches which behave 

 in exactly the same manner as the protonema which proceeds from the spore form 

 chlorophyll, and produce new leafy plants {c/. Fig. 226 and Fig. 229, A, p). In 

 some species (Mnium, Bryum, Barbula, &c.) it is sufficient to keep a turf of moss 

 damp for some days and turned downwards, in order to produce hundreds of new 

 plants in this manner. Some apparently annual species, e.g. of Phascum, Funaria, 

 and Pottia, persist perennially by means of their root-hairs ; the plants disappear 

 completely from the surface of the ground from the time that the spores become 

 ripe till the next autumn, when the root-hairs again produce a new protonema, 

 and upon this new stems arise. 



A similar production of gemmae from the roots occurs also, according to 

 Schimper, in the felted protonema of some species of Polytrichum [P. nanum and 

 aloides) on the slopes of hollow roads, and on that of Schisiostega osmimdacea in 

 dark hollows. The root-hairs may also immediately produce leaf-buds, and behave, 

 in this respect, exactly like the protonema. When the buds arise on underground 

 ramifications of the root-hairs (Fig. 229, B) they remain in a dormant state, as small 

 microscopic tuberous bodies filled with reserve food-material, until they chance to 

 reach the surface of the ground, when they undergo further development {e. g. 

 Barbula murali's, Grimmia pulvinata, Funaria hygrometrica, Trichostomum rigidujn, 

 Atrichum). The aerial root-hairs may, however, not only produce a protonema 

 containing chlorophyll, but also leaf-buds without its intervention ; and Schimper 

 cites the remarkable fact that in Dicrajium iinduJaiwn annual male plants are 

 formed in this manner on the perennial clods of the female plants, and fertilise 

 the latter. 



Even the leaves of many Mosses produce a protonema, their cells simply 

 growing, and the tubes thus formed becoming segm.ented. This occurs in Ortho- 

 trichum Lyelli and obtusifoliiim ; in 0. phyllanthu77i club-shaped tufts of protonema 

 with short cells arise at the apex of the leaves ; and the same phenomenon occurs 

 in Grimmia trichophylla, Syrrhopodon, and Calymperes. In Oncophoriis glaucus 

 a dense felt of interlacing protonema-filaments is formed at the summit of the 

 plant where the reproductive organs are produced, which arrests its further growth, 

 and hence produces at a later period new clumps of young plants. In Buxbaumia, 

 especially B. aphylla, the marginal cells of the leaves form a protonema enveloping 

 them as well as the stem with its filaments. Lastly, even detached leaves, if kept 

 moist, may emit a protonema, as for instance those of Funaria hygrometrica. 



GemmcE, which, like those of the Marchantieae, are stalked fusiform or lenti- 

 cular cellular bodies, occur in Aulacomnion aiidrogynum at the summit of a leafless 

 elongation of the leafy stem {Pseudopodia) ; in Tetr aphis pellucida enveloped by an 

 elegant cup composed of several leaves, out of which they subsequently fall. These 

 latter then put forth protonemal filaments, which produce first of all a flat pro- 

 emhryo; and upon this finally new leaf- buds arise (Figs. 230, 231). 



Finally the deciduous branch-buds of Bryum annotinum may also be considered 

 as organs of reproduction ; as also, according to Schimper, may the branches of 



