262 BOTANICAL GAZETTE [APRIL 
embryos in B. lunularia, but stated that never more than two 
could develop on the small gametophyte. 
In his studies of Helminthostachys, LANG (2'7) found a plurality 
of young sporophytes, and also found and described many small 
aborted embryos, whose arrest in various stages of development 
was due to the supremacy of the larger successful sporophyte. 
Figs. 19 and 20 are from his figures, made by combining several 
sections of the series, and show the existence of embryonic selection 
in Helminthostachys. He also gives habitat data which may be 
taken as evidence that the fertilizations which gave rise to the 
Fic. 19 
Fics. 19, 20.—Fig. 19, arrested embryo (e.): of Helminthostachys beside foot of 
larger embryo (e;); after Lanc (27); fig. 20, two arrested embryos (é2, ¢;) beside 
larger sporophyte (e;); 51, 52, tiers of suspensor; reconstructed from serial photomicro- 
graphs by LANG (27). 
withered arrested embryos occurred at about the same time as that 
of the successful sporophyte plant, and that the aborted embryos 
CAMPBELL (9). Something definite concerning the occurrence of 
embryonic selection may be inferred from this statement in the 
following passage: 
Unicellular embryos are not uncommon, as several archegonia may be 
fertilized and begin to form embryos, but the later stages are not so easily 
found, and it was not possible to secure as complete a series as might have 
been wished. However, the essential points in the development of the embryos 
were made out, and there is no question as to the way in which the young 
sporophytes develop. 
