PITHOPHORACE. 147 
The reproduction of individuals may, however, be effected also in another 
way than by the formation of spores. Besides the specimens which 
form spores, there are others which never do so. These, which are dis- 
tinguished by a richer ramification, transform part of their cells into so- 
called “ prolific cells.” A common vegetative cell grows richer in 
chlorophyll coloured protoplasm and starch, and is thus made fit to form 
anew individual. This the prolific cells do, when they have been made 
free, by the destruction of the mother specimen, by forming a new speci- 
men laterally near their top, in the same manner as a branch—and later 
a system of branches—is formed by a cell in the fertile specimens. That 
the specimens originated by prolific cells have the power of forming 
spores is certain, as well as that specimens forming prolific cells may 
have been originated by spores. I do not know with certainty whether 
specimens forming prolific cells may have been originated by prolific 
cells themselves, but it seems to me in no wise improbable.— Wit- 
rock, l.c. 
Pithophora Kewensis.— Wittr. Mon. p. 52. 
Principal filament of the cauloid part of the thallus, in fertile 
specimens, on an average ‘059 m. thick, with solitary branches 
of only one degree (rarely of two), spores single, partly enclosed, 
partly terminal, the enclosed spores cask-shaped, but more 
elongated, on an average ‘08 m. thick and ‘2 m. long. the 
terminal spores cask-shaped, with the upper end conical and the 
top somewhat rounded, on an average ‘088 mm. thick and ‘219 
mm. long; the rhizoid part of the thallus as a rule unicellular. 
Wittr. Mon. Pithoph. t. 1 f. 8, t. 2f 1-12; t.3f. 1-9; 
t.4£.2-11;4.5 7.9 10, 
In tank, Water-lily house, Kew Gardens. August. 
This singular plant is thought by Wittrock to have been an importa- 
tion from Brazil. It has not been seen in its original locality for two or 
three years. 
Plate LVI, fig. 8. Portion of spore-bearing filament x 20, Fig. 9, 
portion of principal filament with spore formed at the apex of a short 
branch, and another in process of formation in the principal filament 
x 200. Fig. 10, a mature enclosed spore x 200. Fig. 11, part of cell 
from rooting portion of a sterile thread x 200, All after Wittrock. 
