44 
William J. Hodgetts. 
an old Sphagnum protonema which had not had its growth arrested 
by the production of leafy shoots. Oehlmann 1 has shown that 
Sphagnum has hitherto been incorrectly regarded as forming an 
exception to the general rule among Bryophytes that every living 
cell of the plant is capable under favourable conditions, naturally or 
in cultures, of producing protonema, for he found that protonema 
could be formed from isolated leaves and pieces of stem of Sphagnum 
and—a specially interesting point—that this protonema was of the 
same flattened type as that arising from the spore and had the same 
capacity for giving rise to secondary protonemata by proliferation. 
In Andrecea the protonema is extremely polymorphic. Here 
the spore-contents divide before rupture of the coat so as to form 
a mass of tissue—a thing which very rarely occurs in mosses though 
found in a fair number of liverworts—and one or more of the cells 
of this mass then grow out to form either filaments or more often 
branching ribbon-like or cylindrical structures which bear flat leaf¬ 
like appendages, the “protonemal leaves.” The cylindrical proto¬ 
nema may grow erect to form a “ protonemal shoot ” bearing 
“ protonemal leaves.” All these forms of protonema sooner or later 
bear the buds from which the normal moss-plants arise. It may 
be noted that the only form of vegetative reproduction known in 
Andrecea is by the breaking off of branches which give rise to new 
plants. 
Our knowledge of the protonema in the other genera mentioned 
is mainly due to the work of Berggren, 2 who followed its develop¬ 
ment from the spore in Tetraphis, Tetradontium and Diphyscium, 
while recently Jongmans 3 has described the germination of CEdi- 
podium, and Muller 4 and Correns 5 have added new details regarding 
the protonema of Tetraphis. In Buxhaumia, as figured by Roth, 6 
the protonema is a round plate of cells from which filaments arise, 
hence the early stage appears to be much the same as in Andrecea, 
1 Oehlmann, “ Vegetative Fortpflanzung der Sphagnaceen nebst ihrem 
Verhalten gegen Kalk.” Inaug.-Diss., Freiburg, J898. Warnstorf (“ Sphag- 
nales-Sphagnaceae ” in “Das Pflanzenreich,” Heft 51, p. 27) says he has 
never observed such protonemata in nature and that the conditions under 
which Oehlmann obtained them are not likely to be of frequent natural 
occurrence. 
3 Berggren, “ Studier ofver mossornas bygnad och utveckling. ii. Tetra- 
phideae.” Lunds Univ. Arsskr., 1879. 
* Jongmans, “ Ueber Brutkorperbildende Laubmoose.” Rec. Trav, Bot, 
NSerland., t. 3, 1907. 
* Muller, in Engler and Prantl, Teil 1, Abt. 3, p. 167. 
6 Correns, “ Untersuchungen uber die Vermehrung der Laubmoose.” 
Jena (Fischer), 1899. 
6 Roth, “ Die europaischen Laubmoose,” Bd. 1, 1904, Taf. 1, Fig. 4. 
