On THE PITHOPHORACE. 19 
Ill. ON THE GERMINATION AND INCREASE. 
Although I have not had opportunities of immediately observing 
the germination of a Pithophora*), still a close study of the rich material, 
chiefly of P. kewensis nob., which I have had at my disposal, has made 
it possible for me to account at least for the principal moments of this 
act of development. 
The germination of the spores takes place, as a rule, in the fol- 
lowing manner. The spore having been made free by the dissolution of 
the two cells situated one on each side of the spore, and having reposed 
long enough *), it sends forth two conically-cylindrical processes, one 
from each of the two opposite ends of the spore. The spore cell, thus 
developed in a longitudinal direction, is then divided by a parting wall 
into two daughter cells. This parting wall is, it is true, always trans- 
versal, but sometimes obliquely transversa] — as for instance in P. suma- 
trana (v. Mart.) nob. (pl. 4, fig. 1 sg) and regularly in P. kewensis nob. 
Gies2 nie 1, 5, 7 sg, and pl. 4, fig. 4 5: 6, 9 sq), — and, sometimes 
transversal in a straight direction or, in other words, vertical against 
the longitudinal axis of the spore cell — thus as a rule in P. Cleveana 
nob. (pl. 4, fig. 16, 17 sq) and exceptionally in P. kewensis nob. (pl. 4, 
fiz. 7, 8 sg). This parting wall is most frequently situated just at the 
midst of the germinated spore and thus divides it into two almost equal 
parts (pl. 4, fig. 1, 6, 9, 15); but sometimes it is placed a considerable 
space above or below the midst of the spore (pl. 4, fig. 4, 7, 8, 16), thus 
dividing it into two very unequal parts. The two daughter cells, formed 
by the division into two of the spore cell, now increase in two diame- 
trically opposite directions, and give origin one to the cauloid, and the 
other to the rhizoid part of the thallus. The transversal wall which is 
1) My sojourn in Kew was of so short duration, that I had not time enough 
to succeed in any experiments of germination. After my return to Upsala I have 
endeavoured to make spores which have been dry germinate (this succeeds, as is 
known, pretty easily with some alg), but J did not succeed. 
*) That the spores of Lithophoracee are hypnospores may be concluded among 
other things from the fact that their membrane increases considerably in thickness 
during the ripening of the spores, a thing which does not take place in spores intended 
for immediate germination, 
