Recent Discoveries of Pteridophyte Prothalli. 87 
Ceylon and the Malay Peninsula, with the special object of looking 
for the still undiscovered prothalli of the Lycopod Psilotum, and the 
remarkable Ophioglossaceous plant Helminthostachys zeylanica. In 
this quest he was very largely successful. After a vain hunt in the 
best localities for Psilotum in Ceylon, a single prothallus of unknown 
origin was discovered on the trunk of a tree-fern on Maxwell’s Hill, in 
Perak (Malay Peninsula), and there is considerable evidence that it 
belongs to Psilotum / though the possibility exists that it may 
belong to a species of Lycopodium. It conforms pretty closely to 
the type of Lycopodium cevnuum. In the case of Helminthostachys, 
however, complete success was attained. A considerable number 
of the prothalli were found in a damp jungle at Hanwella, near 
Colombo, a locality which Dr. Lang had been led to expect would 
be a suitable one for his purpose. There is no doubt that the 
failure of more than one previous worker to find this prothallus was 
due to searching in dry localities, where the plant spreads by means 
of its underground rhizome and no prothalli are formed. 
The prothallus of Hehninthostachys, of which a full account is 
given in the current number 2 of the “ Annals of Botany,”is a brown 
cylindrical structure, growing by means of an apical cell and bearing 
sexual organs on its sides and summit, and short rounded knob¬ 
like branches covered with rhizoids at its basal end. It is subter- 
ranean and saprophytic, and, like all the known prothalli of this habit, 
infested with an endophytic fungus, which, like that of the legu¬ 
minous root-tubercles, at first aids the plant to manufacture organic 
food, but is eventually killed and presumably used as food by the 
host. 
Dr. Lang also obtained prothalli of the epiphyte Ophioglossum 
pendulum from the same locality. The fronds of this beautiful plant 
hang in long strap-shaped pendants from the mass of humus 
collected by the larger epiphytic ferns such as Asplenium Nidus and 
Polypodium quercijolium , and it w^as in this humus that the prothalli 
were found. The fully-grown prothallus consists of a number of 
cylindrical branches, radiating from a centre. There is an entire 
absence of rhizoids, but the surface is covered by numerous short, 
wide, unicellular hairs. On the sides of the branches the sexual 
organs are borne, and the internal tissues are inhabited by an 
endophytic fungus, apparently identical with that found in the roots 
of the sporophyte. 
1 Bang. Proc. Roy. Soc., 1901. 
2 Lang. On the Prothallus of Ophioglossum pendulum and 
Helminthostachys zeylanica,—Ann. of Bot., March, 1902. 
