258 BOTANICAL GAZETTE [APRIL 
more than one young plant or embryo in fertilized archegonium. The pro- 
thalli of the next named three (L. Billardieri, L. Billardieri gracile, L. varium) 
are of the much branched epiphytic type, with a comparatively bulky central 
region on which the sex organs are borne. I have found that many well grown 
prothalli in all three species have two and even three healthy plantlets. 
Curiously enough, I have not found a single instance of two or more young 
embryos or fertilized archegonia existing on the same prothallus, although I 
have sectioned a large number. 
The prothalli of the last named three (L. volubile, L. fastigiatum, L. scari- 
osum) are large and deep living, the first two belonging to the clavatum 
type and the third to the complanatum type. I have examined a large number 
of each of these both externally and in serial section. These prothalli are of 
course all comparatively large in size, and they frequently have two or three 
developing healthy plantlets. From serial sections I have found on one 
prothallus of L. volubile one young plant and two embryos, and on another 
four embryos. The prothalli of L. fastigiatum supply the most noteworthy 
instances of polyembryony. One large prothallus showed no less than eleven 
embryos in different stages of development and three young plantlets, all of 
these fourteen being healthy. Other prothalli showed from three to five 
embryos. The archegonia in these two species are nearly exclusively on the 
liplike prominence which surrounds the top of the prothallus, so that the 
embryos and plantlets are generally quite close together. In L. scariosum 
I have also found two, three, and four embryos on the one prothallus. 
From my own observations I can say that the large growing prothalli of 
certain Lycopodium types (as enumerated above), and also those of T'mesipteris, 
not uncommonly show polyembryony arising from the fertilization of several 
archegonia. I note, however, that CHAMBERLAIN shows two young plants on 
a prothallium of L. /aterale which is of the small-growing form. 
It is very evident that Tmesipteris and some of the Lycopodiales 
with large gametophytes may mature several sporophyte plants. 
Doubtless some kind of embryonic selection is found even among 
these, as it is highly probable that only a fraction of the zygotes 
produced attain their full term of embryonic development. Several 
young sporophytes, however, are usually produced on various 
parts of the tuberous gametophytes. If these arrested embryos 
remain healthy looking for a long period, a condition definitely 
reported for some, this fact would indicate a more primitive 
condition than that of their complete abortion. 
Such a heterosperous form as Selaginella is much nearer to the © 
condition from which the seed habit was derived. While some 
large vigorous gametophytes of Lycopodium may frequently give 
