Page 298: Revision of Pandanus, 15. Malaya — St. John 
355 
HOLOTYPE: Singapore, on the west coast road 
near Pasir Panjang, Dec. 11, 1911, H. N. Ridley 
15,465 (SING). Holotype examined! 
SPECIMENS EXAMINED: Singapore, Botanic 
Gardens, Aroid Rockery, cult., 20 April 1936, 
E. J. H. Corner 30,993 (kep, sing). 
SECTION Rykia 
Pandanus immersus Ridl., Asiat. Soc., Straits 
Branch, Jour. 41: 48-49, 1903; Mater. 
FI. Malay Penin. 2: 224, 1907; FI. Malay 
Penin. 5: 76, 1925; Martelli, Webbia 
4(1): 18, 1913; (sect. Rykia ) 
Fig. 188 
NOM. VERN.: "mengkuang ayer.” 
DIAGNOSIS OF HOLOTYPE: Aquatic, "the stem 
rising but little above” the surface of the river; 
leaves "many feet long,” 10.2 cm wide, coria- 
ceous, green above, pale and glaucous beneath, 
the longitudinal veins strong, visible above and 
conspicuous below, about 1 mm apart, at mid- 
section with 70 secondary parallel veins in each 
side, the venation also consisting of tertiary 
cross veins 1-3 mm apart, these easily visible 
above and conspicuous below, the base not pre- 
served but the blade 1 -ribbed, 2 -pleated, in sec- 
tion M-shaped, ligulate, narrowing upwards and 
in the upper quarter tapering to a subulate del- 
toid apex about 30 cm long, and at a point 
about 10 cm down from the tip only 1.3 mm 
wide; at about the midsection the margins with 
thorns 2.5-4 mm long, 9-18 mm apart, subulate 
but the base thickened, nearly straight, ascend- 
ing, pale except for the very tip which may be 
reddish; near the tip the margins with serrae 
0.8-0. 9 mm long, 1.5-3 mm apart, stout; the 
midrib below nearly unarmed; pistillate inflores- 
cence apparently emersed; peduncle more than 
8 cm long, 15 mm in diameter, 3 -sided, brac- 
teate; syncarp perhaps a third mature, 9.5 cm 
long, 6 cm in diameter, ellipsoid, 3 -sided, bear- 
ing about 1,440 drupes, these 17-19 mm long, 
5-6 mm wide, 3-4 thick, the body 12-13 mm 
long, arcuate spatulate, upper free, cuneate 
to the base; the pileus 7-8 mm long, the base 
subsemiorbicular, minutely papillose; the style 
4-6 mm long, hornlike, mostly gently curved 
proximally, the apical ones unbranched, of the 
median and lower ones about half are entire 
with a single horn but the other half are bifur- 
cate and the 0.5-2 mm lobes often are wide- 
spreading; stigma 3.5-5 mm long; endocarp 
(immature) oblanceoloid, nearly as long as the 
body; mesocarp fibrous and fleshy. 
HOLOTYPE: Malaya, "Selangor, in the Labu 
River, forming dense thickets,” May 1891, H. 
N. R[idley] , (SING). Holotype examined! 
Pandanus johorensis Martelli, Soc. Bot. Ital., Bui. 
302, 1904; P. muarensis Ridl., Mater. 
FI. Malay Penin. 2: 226-227, 1907, and 
FI. Malay Penin. 5: 77, 1925; (sect. 
Rykia ) 
Figs. 189, 190 
NOM. VERN.: "rassau.” 
DIAGNOSIS OF ISOTYPE: Leaves 1.3-1.45 m 
long, 4.2 cm wide, coriaceous, paler beneath, 
1 -ribbed, 2 -pleated, at midsection with 43 sec- 
ondary parallel veins in each half, no visible 
cross veins, ligulate, gradually tapering to a 
27 cm subulate deltoid apex, this 10 cm down 
O. 7 mm wide, the base amplexicaul, unarmed, 
but beginning at 10-11 cm on one side, and 
at 18 cm on the other the margins with prickles 
1.5-2 mm long, 4-11 mm apart, subulate, as- 
cending, dark reddish; the midrib below begin- 
ning at 8 cm with prickles 3-3.5 mm long, 
12-22 mm apart, stout subulate, arcuate, re- 
flexed; at midsection the margins with prickles 
1-1.5 mm long, 4-14 mm apart, stout subulate, 
arcuate, closely ascending; the midrib below 
with prickles 1.5-1. 8 mm long, 5-45 mm apart, 
stout subulate, arcuate, reflexed or ascending; on 
the subulate apex the margins with serrae 0.5 
mm long, 1-3 mm apart; those of the midrib 
below similar but 3-7 mm apart; peduncle 29 
mm long, 8 mm in diameter, 3 -sided, slightly 
sinuous, leafy bracted; syncarp single, 6 cm long, 
3 cm in diameter, narrowly ellipsoid (very 
young), bearing about 4,096 drupes, these (im- 
mature) 11-12 mm long, 1.5-2. 5 mm wide and 
thick, 5-6-angled, upper 2 A free, the body 4.5-5 
mm long, oblong-ellipsoid, papillose, with thick 
longitudinal fibers; style 7 mm long, setiform, 
hard, shining and yellow; stigma linear, proxi- 
mal, brown, as long as the style; endocarp and 
seed not yet formed, but inside the ovary wall 
