1922] BUCHHOLZ—VASCULAR PLANTS 261 
phytes on a single gametophyte (fig. 17). It is difficult to under- 
stand how only one or a few eggs could be fertilized where 
hundreds of archegonia are found, even if they are of successive 
origin. The result of such a fertilization would produce dozens 
or at least quite a number of zygotes, a majority of which never 
develop beyond the stage of only a few cells, and many probably 
succumb in the struggle for nourishment in the one-celled stage, 
or before they divide many times. E£. laevigatum was recently 
Fic. 17 Fic. 18 
Fics. 17, 18.—Fig. 17, gametophyte - Equisetum debile giving rise to fifteen 
Sass under laboratory culture,X1.5; after KasHyap (26); fig. 18, Eguiselum 
laevigatum, gametophyte bearing four renin 5d after WALKER (38). 
investigated by Miss WALKER (38), and this species likewise ‘thas 
a plurality of young sporophytes, four being shown in one case 
(fig. 18), and six in another. It is evident that embryonic selection 
plays a réle in most, if not all species of Equisetum. Plurality of 
embryos seems to have been found in all carefully investigated 
species. 
OPHIOGLOsSALES.—In his work on the gametophyte of Botry- 
chium virginianum, JEFFREY (25) states and gives illustrations 
of the fact that one frequently finds two or more sporophytes on 
a single prothallium. BrucamMann found many very young 
