MUSCI. 
377 
The same length of time is required by PhilonoHs, and by some species of Bryum 
and some of Polytrichum which blossom in May and June \ 
Mosses may be distributed naturally into four parallel orders :— 
1. Sphagnacese, 
2. Andreaeaceae, 
3. Phascaceae, 
4. Bryaceae (True Mosses). 
Of these the first includes a single genus, the second and third only a few ; the fourth all 
the remaining extremely numerous genera. The first three groups recall, in many 
respects, the Hepaticae ; even the series of true Mosses commences with some genera 
which still resemble that class; the lowest forms of all the groups exhibit many 
resemblances which are wanting in the most highly developed. We have therefore four 
diverging series. 
I. The Sphagnaceae^ include only the single genus Sphagnum. When the spores 
germinate in water, a branched protonema is developed, on which the leaf-buds imme- 
diately appear laterally (Fig. 258, C). 
On a solid substratum, on the other 
hand, the short protonema forms first 
of all a branching flat protonemal 
expansion (Fig. 259), on which (as 
in Tetraphis) the leaf-buds appear. 
The leafy stems produce root-hairs 
only in the young state. The abun- 
dant protonema of true Mosses is 
entirely wanting. The stem, as it 
increases in strength, produces later- 
ally, by the side of every fourth leaf, 
a branch, which, even at the very 
earliest period, is again much divided; 
tufts of branches arranged regularly 
thus arise which form a compact mass 
at the summit of the stem, but lower 
down are more distant from each 
other. The separate branches de- 
velope in difi^'erent ways ; one is pro- 
duced each year beneath the summit 
after the ripening of the fruit, and 
developes in a similar manner to the 
primary stem, growing up along with 
the prolongation of the latter, so that 
each year a false dichotomy takes 
place on the stem. These innovations 
afterwards become separated by the p,^. :,eo.-Spha,nun. acuti/olü.m ; pan of the stem below the 
slow decay of the plant advancin*^ apex the male branches, 5 leaves of the primary stem ; peri- 
' ^ 0 chsetial branch with old still closed sporogonia (after Schimper, 
from below, and constitute indepen- xs-6). 
dent plants. Some of the branches of 
each tuft, however, turn downwards, become long, slender, and finely pointed, and 
are closely applied to the primary stem, forming a dense envelope around it; while other 
^ Klinggräff, Bot. Zeitg. i860, p. 344. 
2 W. P. Schimper, Versuch einer Entwickelungsgeschichte der Torfmoose, Stuttgart 1858 (with 
many beautifiil plates). [Russow, Beitr. z. Kenntn. d. Torfmoose, 1865. — Leitgeb, Wachsthum des 
Stammes und Entwickelung der Antheridien bei Sphagnum, Sitzber. d. Wien. Akad. 1869.] 
