1922] BUCHHOLZ—VASCULAR PLANTS 263 
Of course embryonic selection would tend to make the later 
stages scarce, while the arrested unicellular and smaller embryos 
would be more frequent. Doubtless many of the latter are repre- 
sented by the aborted embryos studied and mentioned by Lanc 
and CAMPBELL. 
LEPTOSPORANGIATE FILicALEsS.—Embryonic selection is also of 
common occurrence in many of the leptosporangiate ferns. In a 
paper on Osmunda, CAMPBELL (7) makes the statement, speaking 
of the O. cinnamomea gametophyte: 
Frequently more than one archegonium is fertilized as in the Gleicheniaceae 
(34), but as a rule only one embryo develops, although it is not at all uncommon 
to find several archegonia where the egg has evidently been fertilized, as is 
shown by its enlargement and investment with a cell wall. Only one case was 
met with where two larger embryos were present, but one of these was very 
much in advance of the other, and it is probable that the larger one would have 
ultimately starved out the other. 
RAUWENHOFF (34) described the occurrence of several embryos 
in Gleichenia (fig. 22); and in Vittoria GorBEL (19) found a similar 
a) 
Be 
BG eR BY 
=e 
Reh 
Sy XS 
Fic. 22 
Fics. 21, 22.—Fig. 21, gametophyte of Vittoria with three embryos (e) on various 
parts of branching thalhus ar, archegonia; after GOEBEL (19); fig. 22, embryos of 
Gleichenia showing noljseobryons: after RAUWENHOFF (34). 
plurality of sporophytes and embryos. He states that he has no 
doubt that several sporophytes may come from a single prothallium; 
at least he frequently noticed several embryos in various parts of 
the prothallium (fig. 21), also prothallia on which there were still 
other embryos in addition to the larger sporophyte. GOEBEL statés 
that it is dependent upon circumstances of nourishment whether 
or not these smaller embryos continue their development. 
