MAY 31 1912 
library 
new yoR K 
botanical 
Bar oen. 
The Nature of the Fertile Spike in the 
Ophioglossaceae. 
BY 
MINTIN A. CHRYSLER, 
Associate Professor of Botany, Univ. of Maine. 
With Plates I and II, and sixteen Figures in the Text. 
S PECULATION on the morphological nature of that unusual organ of 
the Ophioglossaceae known as the fertile segment or fertile spike 
dates at least from the time of Roeper, who in 1836 (20) suggested that in 
Botrychium Lttnaria the leaves arise in pairs, one sterile and one fertile, with 
their petioles fused. In 1843 Roeper extended his views to the whole 
family (21). But Presl (19) pointed out that the base of the petiole (‘stipe ’) 
contains only a single bundle, and hence he considered the fertile spike 
to be a pinna of the leaf. Apparently influenced by this criticism and that 
of Mettenius (17), Roeper in 1859 (22) replaced his earlier suggestion 
by the view that the fertile spike represents two fused pinnae, namely the 
basal ones of a leaf, the rest of the pinnae of which are sterile. He also 
adduced teratological evidence in support of his view, and noted that the 
vascular supply of the fertile spike is double in species of Botrychium. 
It was shown by Holle (14) that Roeper’s theory might be applied to 
Ophioglossum , since the origin of the vascular supply of the fertile spike is 
similar to that in Botrychium. 
The suggestion of Braun (7) that the fertile spike of Ophioglossum 
is the first leaf of a bud in the axil of the ordinary sterile leaf, with which 
its stalk is confluent, has not received wide acceptance. 
Goebel (12, 13) has adduced the view that the fertile spike of Botrychium 
is the lowest fertile pinna of a leaf, but that it arises in a ventral instead of 
a lateral position. 
All of the theories so far outlined assume that the aerial organ of the 
Ophioglossaceae consists of one or more leaves which have been derived 
from the leaf of some fern-like plant by a process of specialization ; in other 
words, that the ancestry of the Ophioglossaceae is to be looked for among 
the ferns. Since Botrychium is the most fern-like genus of the family, it is 
regarded as the primitive genus. 
[Annals of Botany, Vol. XXIV. No. XCIII. January, 1910.] 
B 
