368 
MUSCINF^. 
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. 
Similar outgrowths from the roots occur also, according to Schimper, in 
the felted protonema of some species of Polytrichum {P. nanum and abides) on 
the slopes of hollow roads, and on that of Schisiostega osmundacea 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. 250, B) they remain in a dormant state, as small microscopic 
Fig. 2^0.— a young plant of a Barbula (m) with the root-hairs A, to the growing ends of which particles of earth have 
become attached; at ^ a superficial root-hair is putting out branches containing chlorophyll, in other words a protonema; 
at a tuberous bud (bulbil) is growing from an underground branch of the root-hairs; B this bud more strongly magnified 
X 20 ; i>' X 300). 
tuberous bodies {bulbils) filled with reserve food-material, until they chance to 
reach the surface of the ground, when they undergo further development {e.g. 
Barbula muralis, Grimmia pulvinala, Funaria hjygrometrica, Trichostomum rigidu7n, 
Atrichuni). 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 Dicranum undulatum annual male plants are 
formed in this manner on the tufts of perennial 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 segmented. This occurs in Ortho- 
