Bower. — Ophioglossum simplex , Ridley. 21 1 
of the species of Ophioglossum investigated may then be summed up 
thus : — 
(1) The xylem in the strands of the leaf -stalk at first faces directly 
or obliquely to the adaxial surface : in sterile leaves they constitute a more 
or less extended arc, open on the adaxial side ; but in the fertile leaves 1 , 
and especially clearly in O. pendulum and palmatum , as the strands pass 
upwards from the base the arc closes in, and the strands together constitute 
a ring , the margins of the arc being indistinguishable, and they may be 
related to one another by fusions. In the lamina the ring again opens out 
into a flattened arc, the opening taking place at the insertion of the spike, 
or of the lowest spike where there are several. 
(2) In the spike the strands are always arranged with their xylems 
directed abaxially , in a flattened arc , never in a closed circle. 
Thus diagnostic characters, though of a somewhat imperfect sort, exist, 
marking off the spike from the leaf-stalk. It remains to attempt the appli- 
cation of this diagnosis in the case of O. simplex , with a view to deciding 
the question of the morphological nature of the appendages which it bears. 
The following considerations as regards probable affinity may help towards 
the concentration of the problem down to a definite issue. Mr. Ridley 
suggests that the affinity of our plant is with O. Bergianum and with O. pen- 
dulum : the former affinity I should regard as doubtful, on the grounds of 
form as well as of anatomical character ; the latter affinity seems for similar 
reasons more natural. But the nearest similarity in form is with the ground- 
growing plant designated O. intermedium, Hook., found by Lobb, near 
Sarawak, Borneo 2 . This plant was doubtfully included by Prantl in 
O. pendulum 3 . I think that these three plants constitute a natural group, 
or section of the genus, which may be designated with Prantl, § Ophioderma, 
and be held to consist of three species, viz. O. pendulum , L., O. intermedium , 
Hook. 4 , and O. simplex, Ridley. 
If the probable affinity of our plant be, as suggested, with O. pendulum 9 
the anatomical issue assumes some degree of definiteness ; for we know 
that in O. pendulum the vascular supply in the spike is in the form of 
a flattened arc, with the xylems directed abaxially, while that of the leaf- 
stalk shows the strands arranged in a complete ring, with their xylems 
directed centrally. The question may therefore be put thus : if we find 
in O. simplex that the strands are in a flattened arc and the xylems 
1 Compare Rostowzew, 1. c., Text fig. 2 , p. 7 . 
2 Hooker, Century of Ferns, Tab. xcv. 3 Prantl, 1. c., pp. 331 , 332 . 
4 I see no sufficient reason for sinking this species, as Prantl does doubtfully. The discovery of 
0. simplex seems to me an additional reason for its retention as a valid species. I have compared 
the type specimen of 0. intermedium , at Kew : the habit of the lower part of the plant is very similar 
to that of 0. simplex ; the difference chiefly lies in the presence of the small sterile lamina, and 
winged stalk below its insertion in 0. intermedium, and in a narrower tract of tissue between the 
rows of sporangia of the spike than in 0. simplex , but the latter character is variable in 0. pendulum. 
