198 ANNALS OF THE ROYAL BOTANIC GARDEN, CALCUTTA, (D. periacanthus. 
Descrrption.—Scandent, of moderate size or rather robust. Sheathed stem 3-3°5 cm. 
in diameter. Leaf-sheaths have a small and inconspicuous gibbosity far below the base 
of the petiole, and are armed with comparatively few, large, light-coloured, flat, 2-4 
mm. broad, 3-4 cm. long, solitary, deflexed spines, scattered amongst a large 
number of crowded, ascendent, dark-brown, rigid spiculae, 19-15 mm. long at most ; 
the mouth is obliquely truncate and armed with several, erect, 8—10 cm. long, light- 
coloured, large spines. Leaves large, 2-2:2 m. long in the  pinniferous part, and 
terminating in a robust, long, and powerfully clawed cirrus; petiole very robust, 
about 70 cm. long and 2 em. broad, rather polished, in its basal portion 
sub-plano-convex with rather acute edges, from the middle upwards almost 
equally convex on both surfaces and somewhat flattened; in this portion the edges 
are very acute, and near them, on the lower surface, as also along the centre of 
the dorsum, are a few, scattered, large, strong, broadly laminar, light-coloured spines 5 
further both surfaces, but especially the upper one, are more or less covered 
with small, straight, short and comparatively large, solitary or shortly  seriate 
ascendent spines; the petiole of the lower leaves is terete and armed with remote 
whorls of large light-coloured spines; rachis convex and prickly on the lower portion 
of the upper surface, and superficially grooved at the sides for the insertion of the 
leaflets; from about the middle upwards the rachis is smooth, and has an acute 
salient angle and flat side faces; on the lower surface it is armed with very robust 
claws at first 3-nate, then 5-nate, and on the cirrus half-whorled at short and 
regular intervals. Zeaflets numerous, all on one plane, but aggregated on each side 
of the rachis into several remote groups of 2-5 leaflets in each; the groups are 
subopposite, i.e., those on one side are slightly decurrent to those on the other side; 
the vacant spaces are 10-—20 cm. long; in each group the leaflets are sub-equidistant, 
4-5 cm, apart; they are rather firmly papyraceous, closely and superficialy plicate 
longitudinally, green, faintly glossy on the upper surface, paler and quite dull 
beneath, ensiform or narrowly lanceolate, broadest about their middle, tapering thence 
to & rather acute base, and acuminate towards a subulate, slightly bristly-spinulous 
tip; on the upper surface they have often a broad glossy band along the lower 
margin, and the mid-costa and the secondary nerves slender and sharp, of the 
latter one on each side of the mid-costa being somewhat stronger than the 
others; both surfaces are usually quite smooth, but at times the mid-costa has 
a few bristles underneath near the apex; the transverse veinlets are not sharp 
but excessively numerous, short and interrupted, and give an obsoletely shagreened 
appearance to both surfaces; margins almost smooth from the base up to about 
the middle, and thence minutely spinulous ; the intermediate leaflets in large 
specimens are 50 cm. long and 4 em. broad. Male spadiz erect, rigid; the panicle 
50-70 cm. in length, borne on a strongly flattened pedicellar part, which is 
5-12 cm. long, 8-12 mm. broad and has a few fascicles of flabby light-coloured, 
black-tipped, acicular spines on the edges; primary spathes lanceolate, deciduous, . 
thinly coriaceous, of a cinnamon-brown colour, rusty-furfuraceous externally, finely 
striately-veined; the outermost splits longitudinally along the entire ventral side, 
is two-keeled on the back, and more or less armed on the keels, with fascicles 
of flabby, unequal sub-bristly spinules; inner spathes smooth, each gradually 
protruding beyond the other; the flowering axis is slightly flexuose, more or less 
rusty-furfuraceous ; its internodes are 7-10 em. long, obsoletely angular, not 
