GENERAL MORPHOLOGY 



435 



individual leaf beyond what is typically seen in O. vuigatum, 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 



is not so clearly median as in Fig. A. Fig. 238 D 



FIG. 237. 



, ., .. c ... . Schlecht. Whole plant, 



shows two fertile spikes of equal size, inserted slightly reduced. 

 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 B 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 u, 

 preserved in the British Museum, and to arrange it so that the position 



