The Reproduction of Ahnfeltia plicata. 21 
of Ahnfeltia plicata in Nature often reach a considerable 
size before the formation of upright shoots takes place, — 
The development of the disc-shaped young 
plants from the germinating monospores thus 
tells directly against SCHMITZ's hypothesis. 
4. Conclusions. 
Fig. 18. Young 
frond springing 
The reproduction of Ahnfeltia plicata (and 
related species) is very peculiar and different rom an ex- 
from that of all other Florideæ. Antheridia, panded disc. 
carpogonia, cystocarps and tetrasporangia are N 
wanting. No organs of reproduction are known apart from 
the nemathecia. These bodies are different from other nema- 
thecia known by their development and their function. 
While other nemathecia produce seriate tetrasporangia in 
the nemathecial filaments, those of Ahnfeltia produce mono- 
sporangia only in the last cell of the nemathecial cell- 
rows. But the cell-rows producing the monosporangia are 
not identical with the primary nemathecial filaments. These 
arise in autumn as outgrowths from a group of superficial 
cells of the frond dividing by transverse cell-walls. In these 
cell-rows two kinds of particular cells are early produced 
(in October): 
1) flask-shaped cells arising from the end-cells of 
the cell-rows, most frequently at the bottom of the nema 
thecium and consequently often terminal on the cortical 
cell-rows. These cells remind one of carpogonial cells by 
their shape and like these stain deeply with hæmatoxy- 
lin, but this coloration touches only or in particular the 
cell-wall, whereas the content is feebly developed, homo- 
geneous and apparently slightly stained and the nucleus not 
or scarcely visible. These cells are further terminal on 
