C. dimorphacanthus] ^ BECCARL MONOGRAPH OF THE GENUS CALAMUS, 479 
187. CALAMUS DIMORPHACANTHUS Becc. in Hec. Bot. Surv. Ind. ii, p. 2i4. 
Description.—Slender, scandent.  Sheathed stem 1-2 cm. in diam.. Leaf- 
sheaths short, gibbous above, densely covered with thinly laminar, slender, acicular, 
solitary or shortly seriate, straight, usually horizontal, unequal (5-20 mm. long), 
very light-coloured or substramineous spines. Ocrea very large, 6-7 cm. long, 
papyraceous, shining and almost of a silky hue inside, densely armed externally 
like the sheaths. Leaves rather delicate, elongate and narrow in outline, about 60 cm. 
long in the pinniferous part, petiole very short (4-5 cm. long), flat above, convex 
beneath, armed all round with very slender acicular spines; rachis sub-biconvex in 
the first portion, angular and bifaced upwards in the upper surface where armed 
as wel as at the sides with straight light-coloured horizontal acicular, very 
unequal spines, of which some occasionally, especially near the base in the 
leaves of young plants, extremely slender and as much as 3 cm, in length; further 
the rachis is armed beneath along the middle with light, solitary at first, then 
ternate and in the cirrus 5-nate claws; leaflets numerous, inserted at an angle 
of about 45?,  subequidistant with occasionally a short vacant space interposed 
as if a leaflet were missing, thinly papyraceous, green and subconcolorous on both 
surfaces, small, linear or linear-lanceolate, somewhat narrowing towards the base, subu- 
lately acuminate at the summit, with only the mid-costa distinct and bristly 
spinulous and the side nerves very slender and smooth above; underneath, all 
nerves indistinct and naked; transverse veinlets remote and very short; margins 
rather strongly and spreadingly spinulous; the largest leaflets, those a little above 
the base, 10-20 cm. long, 5-10 mm. broad; the upper ones slightly decreasing 
in length, but not narrower. Male spadiz when very young) elongate, cylindric- 
ous, subulate, sheathed with approximate gradually diminishing spathes, which before 
the anthesis are subimbricate, the summit of one partially covering the base of 
that above; moreover they are adpressedly and thinly rusty-furfuraceous. Female 
spadic very similar to that of C. siphonospathus, elongate, slightly curved, about 
50 em. long, with 5-6 partial inflorescences ; primary spathes very sparingly 
prickly, glabrous, papyraceous, tubular, loosely sheathing and subinflate in their upper 
part, prolonged at the summit into a very short and broadly triangular acute 
point, the lowermost cylindricous, armed with numerous scattered very small horizontal 
slender short spinules, the secondary very slightly spinulous, the others smooth; 
partial inflorescences short, broadly ovoid, rather dense, inserted inside their 
respective spathe with a distinct pedicellar part; the lower ones, the largest, 6-7 
cm, long, with few (4-5) gradually diminishing spikelets on each side; the 
lower of these in the lowest partial inflorescences usually branched ; secondary 
spathes tubular, slightly infundibuliform, loosely  sbeathing in their upper part, 
horizontally truncate and entire at the mouth and shortly apiculate at one side ; 
spikelets inserted far above the mouth of their own spathe, the larger ones about 
2 em, long with 4-5 flowers on each side; spathels shortly cylindricous at the base 
suddenly expanded at the summit into a short truncate limb; involucrophorum 
attached outside its own spathel at the base of the one above, sessile, disciform, 
involucre also disciform or with a broad, circular, flat area for the insertion of the 
flower and a very narrow annular margin; areola of the neuter flower small 
depressed callous. Female flowers very small, 3 mm. long, ovoid; the calyx with 3 
