i57 
Embryo of Botrychium obliquum , Miihl. 
2. The embryo differs in several important particulars from both 
B. Lunaria and B. virginianum . It resembles the latter in having the 
cotyledon well developed, but differs in the endogenous origin of the root, 
in the bipolar arrangement of cotyledon and root, and especially in the 
presence of a suspensor. The embryo is much more like that of some 
species of Ophioglosstim and Danaeci than it is like other species of 
Botrychium. 
3. The stem apex grows from a single apical cell, which is much like 
that of Ophioglossum vulgatum. The young cotyledon also has a single 
apical cell. 
4. There is a single primary vascular strand which extends without 
interruption from the cotyledon into the root. There is no cauline stele, and 
the primary vascular strand is augmented later by additions from the traces 
of the second and third leaves. 
5. The cotyledon has a ternate lamina with dichotomous venation. 
The bundle of the petiole is collateral in structure. 
6 . The root early develops a conspicuous tetrahedral apical cell, and its 
development is much like that of the later roots. The bundle is usually 
diarch, but may be monarch. 
While the similarities in both gametophyte and adult sporophyte 
indicate a near relationship between the species of Botrychium , the remark- 
able differences in the embryo and young sporophyte of the three species 
investigated may warrant a division of the genus into three. B. Lunaria , 
B. obliquum , and B. virginianum represent three types of adult sporophyte 
which differ in a number of particulars, viz. form, texture, and venation of 
the leaf ; size of sporangium ; position of sporangiophore ; character of 
leaf-base. 
Prantl 1 recognizes two subgenera, Eubotrychium and Phyllo trich iu m , 
while Milde 2 divides into Eubotrychium and Osmundopteris. The first 
includes all of the species except B. virginianum and B. matricariaefolium. 
Most of the species of Eubotrychium belong to the £ Ternatum’ group, of 
which B. obliquum is an example. These have a fleshy, ternately compound, 
sterile leaf-segment, while the stalk of the sporangiophore is inserted close 
to the base of the petiole. 
Should further investigation show that the other species of the Ternatum 
group agree with B. obliquum in the structure of the embryo, there would 
be ample reason for accepting Lyon’s genus Sceptridium. 
The writer believes that B. virginianum differs sufficiently from the 
other species to warrant raising Osmundopteris to generic rank, and restrict- 
ing the name Botrychium to B. Lunaria and its near allies. 
1 Ber. d. deutsch. hot. Ges., i. 349. 
2 See Underwood: Our Native P'evns, p. 132, 1888, 
