88 THE OPHIOGLOSSALES 



in the number of roots, but in most cases two were found connected with each leaf, 

 instead of one as I stated in my earlier description of the plant (Campbell 4). The 

 roots are very stout, sometimes attaining a diameter of over 3 millimeters. The smaller 

 roots are diarch, but in the large roots there may be three, four, or even five xylems. 



Ophioglossum pendulum is much the largest member of the Ophioglossaceae 

 and the sporangial spike as well as the individual sporangia far exceeds in size those 

 of any other species (plate 4, B, 3-6). The spike is attached by a short peduncle and 

 hangs down from the pendent lamina. In large specimens the spike may reach a 

 length of 20 centimeters or more with a breadth of about a centimeter. Above the 

 insertion of the spike the leaf is thin, but the slender peduncle is continued downward 

 into a thick, flattened midrib which merges gradually into the petiole, so that the 

 spike has very much the appearance of being a terminal structure with the sterile 

 lamina adherent to it. 



The young leaves in 0. pendulum emerge while they are still very young and 

 the sporangial spike is in an extremely rudimentary condition The general devel- 

 opment of the leaf is therefore very easy to follow in this species, as these young 

 leaves are entirely free. 



The second species of the section Ophioderma is the rare O. intermedium 

 (fig. 69; plate 4, A). This for a long time was known only from one locality in 

 Borneo, but has lately been collected at other points in the Malayan region. The 

 specimens figured were collected by the writer near Buitenzorg in Java. In the 

 account of the Ophioglossaceae given in Engler and Prantl's "Natiirliche Pflanzen- 

 familien" (Bitter 2) it is suggested that 0. intermedium is only a terrestrial form 

 of 0. pendulum; but there is no doubt at all that it is a very distinct species. The 

 plants described here were growing in masses of humus at the base of old clumps of 

 bamboo. The stem is usually very short, forming a small tuberous body, from which, 

 in most cases, only a single leaf was growing, although two were sometimes found. 

 A careful examination of this short rhizome showed that, like Ophioglossum pendu- 

 lum, it is dorsiventral. The roots were short and in all cases observed were without 

 branches. In one of the specimens a bud very similar indeed to the corresponding 

 buds in 0. pendulum was found growing from one of the roots. Ophioglossum 

 intermedium differs from 0. pendulum in being rigidly upright. The peduncle is 

 longer and the lamina of the leaf much smaller and more clearly differentiated from 

 the petiole. As in 0. pendulum, however, the petiole is prolonged into the peduncle 

 of the spike with the same midrib-like thickening, caused by the coherence of the 

 basal part of the peduncle with the lamina. 



This plant is exceedingly variable. In the larger specimens, except for the much 

 shorter lamina, the plant a good deal resembles small specimens of O. pendulum. 

 In others, however, the lamina is almost completely suppressed and this condition 

 closely approaches the third member of this section, Ophioglossum simplex (fig. 71). 

 This latter species is at present known only from one locality in Sumatra, and is dis- 

 tinguished from all the other species of Ophioglossum by the practically complete 

 suppression of the sterile portion of the leaf (see Bower 8). The form of the rhizome 

 and the habit of the plant in O. simplex most nearly resemble 0. intermedium, to 

 which it is probably not very distantly related. Whether or not we regard the 

 absence of the lamina of the leaf as a case of reduction, the fertile leaf in 0. simplex 

 certainly very closely resembles what one would assume to have been the primitive 

 condition of the leaf in the ancestors of the Ophioglossaceae. 



The third section, Cheiroglossa, contains a single very peculiar species, O. 

 palmatum (plate 5). This occurs throughout tropical America, but does not seem 

 to be a common plant. It has been reported from Florida, where, however, it is 



