Yapp. — Two Malayan ‘ Myrmecophilous' Ferns . 207 
brown in colour. The spores are tetrahedrally arranged, are 
slightly curved with blunt, rather narrow ends, and have 
smooth outer walls. 
II. Polypodium sinuosum, Wallich. 
External Morphology. 
(a) Stem. The rhizome resembles that of Polypodium 
car nosum in its dorsi-ventral structure, the lower surface 
(which bears the roots) being flattened, except near the 
growing point ; also in its swollen, fleshy habit, and in the 
distichous arrangement of its leaves, which are similarly 
borne on prominent swollen leaf-cushions. It is, however, 
smaller ; my specimens rarely have a greater width than 
1-4 cm., though the plant may attain a larger size than this, 
Christ 1 stating that they are 3 cm. broad. 
The surface of the rhizome (including the leaf-cushions) is 
densely covered near the apex with adpressed, imbricating 
peltate scales, which arch over and protect the growing point. 
On the older parts they become somewhat more scattered, 
owing to the elongation of the stem. They are found, though 
rather more sparingly, on the lower surface 2 as well as the 
upper. These scales are nearly orbicular in shape, usually 
about 1 mm. in diameter, and are composed of numerous, 
radially arranged cells 3 . The centre is black and slightly 
raised, and is surrounded by a brown zone, while the margin 
of the scale is white and scarious. 
The leaf-cushions are less swollen in the transverse direction 
than in P. carnosum , and are not placed so close together, two 
consecutive cushions of the same side being often as much as 
4 or 5 cm. apart. 
The branching in the two Ferns is similar, but much less 
frequent in P . sinuosum. It is, however, usual to find at 
1 Christ (’97), p. 112. 
2 Christ, loc. cit., only describes the scales on the upper surface. 
3 See figure in Diels (’99), p. 320. 
