I T 2 
APPENDIX. 
On October 2, after a temporary absence, 1 found that some 
water had been spilt over the object under examination, partly 
burying it in soil ; on removing which I found that it had sent 
several long threads from the lower end into the soil, and that the 
upper ones had either aborted or been broken off, as nothing but 
short projections remained. At this date the shape had materially 
altered in the prothallus direction, having flattened out laterally in 
the same plane as the soil, and formed an incipient but unmis- 
takable sinus (figs. 4 and 5). Since that date growth has continued, 
though slowly, with the result that it is now an undoubted 
prothallus, though much thicker in substance than those produced 
by extension of the pinnule-tips. 
From these observations it will be seen that the formation of 
the prothallus in this case is preceded by a very different series 
of phenomena from those already recorded. In the one case the 
prothalli are simple extensions of the cellular substance of the tips 
of the pinnules, commencing at points quite beyond the venation, 
and, so far as I have observed, produce no root-hairs unless 
brought into contact with the soil. In the other case, however, 
the prothallus is a direct outgrowth of the tip of a veinlet pro- 
truded through the upper surface of the pinnule, and at once 
produces root-hairs in abundance long before it assumes any other 
characteristic of a prothallus ; and, finally, the resulting pro- 
thallus is much thicker in substance. Whether archegonia or 
antheridia are present upon the solitary specimen I have had 
under examination I cannot say, as the disturbance necessary 
for microscopic scrutiny would probably have been more destruc- 
tive than profitable. 
■ These excrescences, it will be observed, bear several striking 
resemblances to the pear-shaped pseudo-bulbils first observed in 
Athyrium Filix-foemina, var. Clarissima. Their size, shape, and 
the production at an early stage of radiating root-hairs are 
Aposporous excrescence in P. axg. polciterrimum Wills. 
