362 
MUSCINEM. 
Mosses both in the structure of the sporogonia, and in the mode of formation of 
the protonema. The spores of the Sphagnaceae produce, at least when they grow 
upon a firm substratum, a flatly expanded plate of tissue, which branches at the 
margin, and produces from its surface the leafy stems. In Andrecea, according 
to the investigations of Kühn, the contents of the spore divide, while still within 
the closed exospore, into four or more cells, and a tissue is thus formed similar to 
that produced in the spores of some Hepaticse (as Radula and Frullanid) ^ : finally, 
from one to three peripheral cells grow into filaments which extend over the 
hard stony substratum. The branches of the protonema may now develope further 
in three different ways; longitudinal as well as transverse divisions arise, and 
irregularly branched cellular ribbons are formed ; or, divisions also taking place 
in addition parallel to the surface of these ribbons so that they come to be several 
layers thick, the protonema developed in this manner as a mass of tissue becomes 
Fig. ■2i,T.—F2iiiaria hygromeirica ; A g-enninating spores; v vacuole; iv root-hair; s exospore; B part of a developed 
protonema, about three weeks after germination; h a procumbent primary shoot with broivn wall and oblique septa, out 
of which arise the ascending branches with limited growth; A' rudiment of a leaf-bearing axis with root-hair w (.1 x 550; 
B about 90). 
erect and branches in an arborescent manner; finally, in the third form, the leaf-like 
branches of the protonema are plates of tissue of simple definite outline. Closely 
allied to this last form is the flat protonema of Tetraphis and Telradoniium, which, 
as will be further shown in a following illustration, arises at the end of longer and 
slenderer filaments^. 
The buds which develope into the Moss-stems apparently never arise at the 
end of one of the principal protonemal filaments, but as lateral branches upon 
them. The idea suggested by me that the protonema, as also the equivalent 
rhizoids of the Bryinese, represent a very rudimentary much elongated Moss-stem, 
just as the branches with naked base of Chara are merely simple forms of its 
stem, has been proved correct by the observations of Schuch (i 870-1871) made 
^ In true Mosses also (as Bartramia, Lencobryum, Mnmrii, and Hypnuni) the first septum of the 
protonema is formed, according to Kühn, even within the spore. 
^ Compare Berggren, Bot. Zeitg. 1871, 
