207 
Bower . — Ophioglossum simplex , Ridley. 
the external observation of the mature parts of the specimen affords no 
evidence of any sterile lobe or lamina, as in the known Ophioglossaceae. 
Mr. Ridley speaks of the ‘ almost complete suppression of any trace of 
a sterile portion of the frond 5 ; I find in the specimen sent to me no need 
for the qualifying word c almost.’ 
The small appendage at the base of the plant was removed with care, 
soaked out, and examined. It appears to have been compressed in drying, 
and after soaking the form is not recovered. As far as form is concerned 
there is nothing distinctive, while its oblique position on the specimen as 
received would allow of its being either a root or a young leaf displaced in 
the pressing. To decide the point, the whole appendage was removed and 
embedded ; sections then showed that it is a root, and the following 
structural points were observed. 
The stele appears to be of the usual type ; it is diarch, and the xylems 
may remain separated by parenchyma-cells, which occupy the centre. The 
phloem forms an arc on either side, while even in these sections, which only 
partially recover from the pressing and drying, an endodermis can sometimes 
be traced. Outside this is a broad zone of cortical parenchyma, rather 
thin-walled ; this merges into a peripheral band which contains the c gru- 
mous ’ masses characteristic of mycorhiza : notwithstanding the only partial 
recovery of the section from drying, there is no room for doubt that the 
root has been mycorhizal, evidences of the presence of the fungus being 
seen in some four or five layers of the outer cortex. The periphery of the 
root is occupied by a layer of cells with their outer walls much thickened ; 
the thickening sometimes extends to the inner walls as well : this layer 
appears to be of the nature of an exodermis, for at some points remains of 
an outer layer are still to be seen. 
Comparison with O. pendulum shows that the details thus described 
correspond in the main to those there seen : the stele may, it is true, 
have more than two protoxylem groups in O. pendulum , but that character 
is known to be variable in that species. The characters of the cortex 
are very closely matched, including the mycorhizal band and the layer 
(probably exodermis) with the thickened outer wall. These details serve 
to strengthen the comparison of our plant with O. pendulum 1 . 
Since the external form of the mature appendages gives no indication 
of the existence of a sterile lamina, it will be well at this point to consider 
what views are open to us as to their nature in this remarkable plant. 
Two alternatives are possible, (i) that the appendages are spikes pure 
and simple, without any structural evidence of the subtending lamina 
1 Compare Atkinson, Bull. Iowa Bot. Club, xx, 1893, p. 356, on Symbiosis in the roots of the 
Ophioglossaceae: also Janse, Ann. Jard. Bot. de Buitenzorg, xiv, p. 65, PI. IX, Figs. 11, 12, 
I have not however in either species noted the infection as local ; it appeared to me to extend all 
round the cortex. 
