Revision of the Genus Pandanus Stickman, Part 18 
Pandanus of Christmas Island, Indian Ocean, and 
of the Anamba Islands, Indonesia 
Harold St. John 1 
From Christmas Island in the Indian Ocean 
H. N. Ridley described two species of Pandanus. 
As these were never illustrated, they are given 
a revised treatment here. Previously Martelli 
had described a species from the same island, 
based solely upon fragmentary staminate ma- 
terial. The material of these species in the 
herbarium at Singapore has been studied anew 
and is here reported upon. 
In the same herbarium is good material of a 
Pandanus from the Anamba Islands, at the 
northwest border of Indonesia. 
section Pandanus 
Pandanus elatus Ridl. (sect. Pandanus ), R. Asiat. 
Soc, Straits Br., Jour. 45:239-240, 1906 
Figs. 215, 216 
DIAGNOSIS OF LECTOTYPE: Tree; trunks few 
and together, 13.3-20 m tall, 15 cm in diameter; 
bark gray and sparingly thorny; prop roots few, 
hard, short; leaves 1.77-2.1 m long, 8-10 cm 
wide, coriaceous, furrowed above the midrib, 
2 -plicate, in section M-shaped, at midsection 
with 50-52 parallel secondary veins in each half, 
tertiary cross veins visible below in outer third 
forming short oblongs or rhombics, blade ligu- 
late, tapering into a trigonous, subulate apex 
about 10 cm long, this about 5 cm down 1 mm 
wide, the base not seen, near the base the mar- 
gins with spines 2-4 mm long, 4-7 mm apart, 
the first conical and divergent, the others subu- 
late, ascending from a conic base, the tips red- 
brown; the midrib below near the base with 
spines 3 mm long, 11-22 mm apart, with a 
heavy conic base and a subulate reflexed tip; at 
midsection the margins with prickles 3-3.5 mm 
long, 4-10 mm apart, arcuate subulate, flattened; 
1 B. P. Bishop Museum, Honolulu 17, Hawaii, 
U.S.A. Manuscript received October 17, 1961. 
the midrib below with prickles 2.5-3 mm long, 
10-25 mm apart, broad subulate, flat, arcuate 
ascending; on the subulate apex the margins 
and midrib below with subulate serrulations 
0. 3-0.6 mm long, 1-3 mm apart; peduncle "2 
feet long and 2Vz inches thick”; syncarp solitary, 
30-33 cm long, 17.5 cm in diameter, "oblong”; 
phalanges 7. 5-7.7 cm long, 4.5-5. 5 cm wide, 
3.1-4 cm thick, cuneate-obovoid in profile, 6-7- 
angled, the side gently curving, smooth, shining, 
when dried brown, upper free, the apex con- 
vex, lateral sutures mostly distinct, narrow and 
deep, central apical sinuses 5-20 mm deep; 
carpels 9-12, the apices lance-pyramidal, the 
outer ones more or less diverging, the inner 
erect and Vz~\ A the size of the outer; stigmas 
3-3.5 mm long, cordate, sharply oblique and 
centripetal, creased, brown, flush; proximal sinus 
usually running to the valley bottom; endocarp 
submedian, 35 mm long, bony, blackish brown, 
the lateral walls 3 mm thick, the inner surfaces 
shining; seeds 18-20 mm long, 5-6 mm in 
diameter, oblique ellipsoid; upper mesocarp cav- 
ernous in each carpel apex, with pale pith and 
a few fibers; basal mesocarp fibrous and fleshy. 
STAMINATE PLANT: Leaves 1.78 m long, 5.5 
cm wide, at midsection with 35 parallel second- 
ary veins in each half, tertiary veins obscure, 
near the base the margins with prickles 1.5 mm 
long, 4-9 mm apart, stout arcuate subulate, 
ascending, brown-tipped; the midrib below with 
prickles 13-18 mm apart, heavy based but the 
tips broken off; at midsection the margins with 
prickles 1-1.5 mm long, 3-5 mm apart, stout 
subulate, flattened, arcuate ascending; the mid- 
rib below with prickles 1 mm long, 18-32 mm 
apart, arcuate, conic, ascending; on the subulate 
apex the margins and midrib below with subu- 
late serrations 0.2-0. 3 mm long, 1-2 mm apart; 
staminate inflorescence 45 cm long; peduncle 
fleshy; bracts colored, softer than the leaves; 
lowest floral bract 40 cm long, 4 cm wide, lance- 
113 
