Notes . 
385 
all resemblance to true sporangia and, without reaching the stage 
at which the archesporium generally appears, had grown into a sort 
of irregular prothallus. Fig. 20 represents one of these prothalli, not 
at all to be confounded with the scales or paraphyses found in the 
sori of Pteris . In the particular case figured, a trace of what might 
possibly have been a small aborted archesporium could be seen a short 
distance below the terminal cell a. A secondary apical cell had 
formed at 5 , but it is impossible to 
surmise what its further growth 
would have been; it should, how- 
ever, be remarked that, in some 
cases not here figured, there was 
not only a terminal prothalline 
growth, but also a lateral outgrowth 
of similar character from sporangia 
in which the normal development 
had advanced considerably farther 
than in the case shown in Fig. 20. 
It is to be regretted that the 
subsequent growth of these pro- 
thalline structures could not be 
watched. At the time my speci- 
mens were gathered there was no trace of the formation of antheridia 
or archegonia ; but it is not improbable that those organs might have 
developed later in the season. As it is, we have here another instance 
of the reversion of sporangia to structures which are, to say the least, 
prothalline in appearance. I have been informed by a person to 
whom my specimens were shown, that in a certain field in Pennsyl- 
vania the plants of Pteris frequently have an abnormal appearance 
like that shown in Fig. 17. It is to be hoped that hereafter some 
botanist, recognizing the peculiar deformity of Pteris here described, 
will be able to w 7 atch the development of the abnormal sporangial 
growths late in the season. It is certainly worthy of note that the 
abnormal pinnae bore some nearly mature sporangia at a season 
of the year when the normal pinnae showed only very young spo- 
rangia. One would ask whether the premature development and the 
accompanying abnormal growths were, in any way, the result of the 
extraordinary heat of the summer of 1887. 
W. G. FARLOW, Cambridge, Mass. 
