APPENDIX. 
114 
APOSPOROUS LASTREA (NEPHRODIUM). 
Extracted from the Linnean Society’s Journal — Botany, vol. 
xxix. Notes upon an Aposporous Lastrea (Nephrodium). 
By C. T. Druery, F.L.S. (Read November 3, 1892.) 
(Plate xxxiv.) 
The term apospory has been applied to two abnormal modes of 
reproduction discovered within the last few years upon certain 
varietal forms of Athyrium Filix-foemina and Polystichum angulare, 
and subsequently upon some exotic specie. In the Athyrium 
(A. Filix-foemina, var. Clarissima) the usual sites of the sori are 
occupied by clusters of cellular excrescences furnished with an 
indusium, and formed by abnormal development of the sporangia. 
These excrescences, by expansion of their tips, grow out into 
normal prothalli, which produce plants of the approximate parental 
type when pegged down upon the surface of suitable soil. The 
spore is thus eliminated from the life-cycle. I exhibit a panful of 
pinnm showing the early stages of development of the prothalli. 
In the case of the Polystichums, of which several examples exist, 
all of similar type (i.e., P. angulare, var. pulcherrimum), though 
found as solitary sports in widely separated localities, a similar 
type of soral apospory is found upon some of them ; but they are 
further characterised by prothalli being also formed independently 
altogether of the sorus by simple extension of growth of the apices 
of the ultimate divisions of the fronds, or more rarely upon 
extruded venules near their extremities. These prothalli, how- 
ever, can scarcely be considered as normal, being very eccentric 
in shape ; and though archegonia and antheridia are proJuced, and 
plants have been raised by their interaction, these differ widely 
from the parental type, are weakly in constitution, and irregular 
in growth or form. The plants which 1 have raised from the 
soral outgrowths of P. angulare, var. pulcherrimum, Moly, are also 
defective and lacking in vigour. This, however, is not the case 
with the Athyrium, the aposporous offspring of which are robust 
and fairly typical. It was my good fortune to discover soral 
apospory in Athyrium Filix-foemina, var. Clarissima, and Mr. G. 
B. Wollaston followed with the discovery of apical apospory in 
Polystichum angulare, var. pulcherrimum, Padley ; and in the 
latter it will be seen that the life-cycle is still more shortened by 
the elision of not merely the spore, but of the sporangium and 
entire soral apparatus. 
So far the phenomenon has only been remarked on adult 
plants, and the case, therefore, to which my present notes relate 
is new to the extent (1) that not merely apical, but a sort of pan- 
