502 
BOTANY: D. H. CAMPBELL 
Proc. N. a. S. 
to the use of the alloys which Director C. K. Guillaume, of the Bureau 
International at Sevres, has spent so much time in perfecting. I shall 
hope to report observation with these in the future. 
^ Advance note from a Report to the Carnegie Institution of Washington, D. C. 
THE GENUS BOTRYCHIUM AND ITS RELATIONSHIPS 
By D. H. CAMPBBLiy 
Department of Botany, Leland Stanford Jr. University 
Read before the Academy, April 27, 1920 
The genus Botrychium comprises about thirty-five species of almost 
world wide distribution. Up to the present our knowledge of the life 
history of these ferns has been confined almost exclusively to two species, 
B. lunaria (L.) Sw., and B. Virginianum (L.) Sw. 
In 1910, Dr. H. L. Lyon^ published a brief account of the embryo of 
B. obliquum Miihl, which differed so much from the two species mentioned, 
that he proposed to separate B. obliquum as the type of a new genus, 
Sceptridium. 
Dr. Lyon made quite complete collections of material of this species, 
and also prepared series of microtome sections of the gametophyte and 
young sporophyte. This material, as well as similar material of some 
other species, was collected in the vicinity of Minneapolis. 
Dr. Lyon very generously turned over this valuable material to me, 
so that I have been able to make a fairly complete study of the early 
development of this interesting species. 
The gametophyte of B. obliquum, like that of the other species, is 
subterranean. It closely resembles in its general structure that of B. 
lunaria, and B. Virginianum, and in size is intermediate between them. 
The mature gametophyte is a somewhat flattened tuber, 3-6 mm. 
in length and about half as wide. Upon the upper side is a more or less 
conspicuous median ridge upon which the reproductive organs, archegonia 
and antheridia are borne. These closely resemble those of the other 
species, but the spermatozoids are considerably larger. 
The embryo differs remarkably from that of the other species. A very 
conspicuous suspensor is developed, which is wanting in the other species, 
and the relations of the first leaf and root are different. 
The fertilized egg becomes much elongated, and forces its way down- 
ward into the tissues of the gametophyte before any cell-division occurs. 
The first division is transverse, and cuts off a large basal cell, which be- 
comes the suspensor. The smaller terminal cell gives rise to the organs 
of the embryo-sporophyte. 
The further development of the embryo is more like that of the Marat- 
tiales, especially Danaea, than it is like the other species of Botrychium. 
