GENERAL MORPHOLOGY 435 
individual ‘leaf beyond what is typically’ seen in O. vulgatum, though 
characters which are usual in such species as O. pendulum or palmatum 
appear as occasional abnormalities in O. vulgatum 
and other species. The large series of examples in 
the-Herbaria of Kew and the British Museum have 
been examined in order to elucidate these amplifica- 
tions, and among the specimens compared gradual 
steps of progression are illustrated from the con- 
dition with a single spike to the most complex types 
of O. palmatum. Some of these are here illustrated. 
Fig. 238 a shows a specimen in which a single fertile 
spike rises from the adaxial surface of the frond, 
and it may be seen that the vascular bundles directly 
below its insertion continue upwards, and supply the 
centre of the sterile frond; the position appears to 
be exactly median, as in O. vulgatum. The specimen 
shown in Fig. 238 c also has a single fertile spike, 
but its position relatively to the two-lobed sterile frond Fic. 237. 
is not so clearly median as in Fig. a. Fig. 238 p Ophioglossum Bergianum, 
shows two fertile spikes of equal size, inserted Ae eee Dew 
almost symmetrically on the adaxial face of the 
four-lobed sterile frond; such a specimen, when looked at alone, might 
be thought to support the view suggested by Roeper, and adopted 
by others, that the fertile spike is the result of coalescence of two 
lateral lobes or pinnae; but a comparison of other specimens shows 
that no such view can be consistently supported, and Fig. 238 E shows 
a case which it would be difficult to bring into harmony with it; 
for here there are three fertile spikes of almost equal size, all inserted 
clearly on the adaxial surface of the sterile frond. The next specimen 
(Fig. 238 F) shows a larger number of fertile spikes, eight in all; 
every one is inserted well within the margin, on the surface of the 
frond, and in close relation to vascular bundles which supply the central 
part of it. Of the eight spikes, six are associated in pairs upon a common 
stalk, a character which is frequent in specimens where the number of 
spikes is large. Fig. 238 G shows one of the most elaborate specimens 
in the whole series, with 14 fertile spikes, of which only one is really 
marginal. Here again certain of the spikes are associated together, 
especially the lowest group of three, which have a common stalk of inser- 
tion. Sometimes, however, the fertile spikes are distributed with some 
nearer approach to regularity than in the above samples, and it is doubtless 
upon such specimens as that shown in Fig. 238 8 that the descriptions 
of previous writers have been based. But it is to be remarked that such 
specimens are by far the least common among the herbarium plants 
examined. I was permitted to soak out the specimen shown in Fig. 238 8, 
preserved in the British Museum, and to arrange it so that the position 
