561 
of mine. Referring the reader for details to the latter, 
I shall here shortly give its substance, using again 
most of its illustrations. 
The nemathecia form small cushions on 
the surface of the frond, orbicular or usually 
elliptical or oblong in outline (fig. 550). They 
arise in September from a group of superficial 
cells growing out simultaneously and dividing 
by cross walls (fig. 551). In September the 
cushions were only 1—2 cells high; in the 
middle of October the nemathecial cell-rows 
had grown longer, and the nemathecia had 
attained a larger extension by continued produc- 
tion of new nemathecial filaments at the margin 
(fig. 552). The continuity of the nemathecial fila- 
ments with the cortical cell-rows was stated in 
Wee nel 
a Øg HR 
Sean FEU 
Fig. 552. 
| SSIES 775) 2 
CSI 
a) 
®) 
SAGE 
Fig. 553. 
Ahnfeltia plicata. From a nemathecium, 
October. A, nemathecial filaments show- 
ing flask-shaped cells below and genera- 
tive cells above. B, upper end of primary 
nemathecial filament. C, flask-shaped 
end-cell. 1080 : 1. 
1930 by GREGORY Ahnfeltia plicata. Nemathecium, October. A, 
vertical section, 244:1. B—D, upper ends of 
and CHEMIN. The nemathecial filaments with generative cells. 
first-named author 670 : 1. 
maintained that 
the development of the cushion begins with a localized 
hypertrophy of the cortical tissue of Ahnfeltia. The 
nemathecial filaments are very thin, often only 2—3 u 
broad. At this period (October) two kinds of cells 
different. from the others appear. 1) flask-shaped 
cells, attenuated upwards, often appear in great 
number at the bottom of the nemathecium, arresting 
the growth of the filaments on which they are 
terminal (fig. 553). They have some resemblance 
to carpogonia but are not borne on particular cells 
comparable to carpogonial filaments and have only 
a small and feebly developed nucleus, and they 
cannot, therefore, be considered as true carpogonia but 
might probably better be interpreted as reduced hair- 
cells (comp. K. RosENVINGE 1931, p. 8). 2) genera- 
tive cells, thicker and richer in contents than the 
other cells, terminal or lateral, arise at the upper end 
of the nemathecial cell-rows, singly or in small groups 
which seem to arise by division of a single cell. The 
generative cells or some of them grow out, at first in 
particular in a horizontal direction, forming more or less irregular cell-rows, the 
cells of which are larger than the sterile cells. Some of them may be rather hyaline 
D.K. D. Vidensk. Selsk. Skr.,7, Række, naturvidensk. og mathem. Afd., VII, 4. 
72 
