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aurantiaco-rubris et luteis parte 34 supera libera 
5-6-angulosa, apice convexo lateribus subcurva- 
tis vel subplanis laevibus lucidis, suturis laterali- 
bus nullis, sinibus centralibus apicalibus 3-4 
mm profundis anguste V-formatis in centro 
recto vel subcurvato, carpelis 7-11 plerumque 
8-10 apicibus obtusis vel depresse obtusis pyra- 
midalibus, parte 34 infera carnoso-incrassata, 
stigmatibus 2-2.5 mm longis elevatis horizon- 
talibus vel obliquis suborbicularibus vel cordatis 
vel transverse ellipticis sulcatis brunneis papil- 
losis centripetalibus, sinibus proximalibus latis 
ad fondam extensis, endocarpio subsupra- 
mediali 2 cm longo osseoso obscure mahogani- 
colorato lateribus 1.3-1. 5 mm crassis intra 
laevibus lucidis, seminibus 9-11 mm longis el- 
lipsoideis, mesocarpio supero in apice carpelae 
quaeque cavernam cum membranis albis et fibris 
paucis formanti, mesocarpio basali fibroso et 
carnoso. 
DESCRIPTION OF ALL SPECIMENS EXAMINED: 
Treelike, 2.7 m tall; leaves 1.01-1.53 m long, 
4-5 cm wide, coriaceous, green above, slightly 
paler green below, furrowed above the midrib, 
with 2 rounded lateral pleats, at midsection with 
38-42 secondary parallel veins in each half, 
tertiary veins not evident, blade sword-shaped, 
tapering gradually from the base to the 15 cm 
trigonous subulate apex, this 10 cm down 4 mm 
wide, the base amplexicaul and unarmed, pale, 
but beginning 4-5 cm up the margins with 
prickles 1.5-5 mm long, 3-12 mm apart, subu- 
late, ascending, pale; the midrib below begin- 
ning at 11 cm with prickles 1.5-2. 5 mm long, 
13-21 mm apart, stout arcuate subulate, re- 
flexed; at midsection the margins and midrib 
below with prickles 2-2.5 mm long, 4-8 mm 
apart, subulate, appressed ascending, brown- 
tipped; on the subulate apex the margins and 
midrib below with serrulations 0.2-0. 5 mm 
long, 1-8 mm apart; infructescence pendent, 
with one syncarp; peduncle 20 cm or more in 
length, leafy bracted; syncarp 19 cm long, 11 
cm in diameter, narrowly obovoid-ellipsoid, 
perceptibly 3 -sided, bearing 70 phalanges, these 
4.5-5 cm long, 2.8-4 cm wide, 2. 4-3. 4 cm thick, 
pyriform, orange-red and yellow, upper 34 free 
and 5-6-angled, the apex convex, the sides 
gently curved or almost plane, smooth, shining, 
lateral sutures none; central apical sinuses 3-4 
mm deep, narrow V-shaped only at the center, 
straight or gently curved; carpels 7-11, mostly 
8-10, the apices from obtuse to low obtuse 
pyramidal; lower 34 of phalanges fleshy en- 
larged, as shown by the persistent shoulders; 
stigmas 2-2.5 mm long, elevated, horizontal or 
oblique, suborbicular, cordate, or transversely 
elliptic, creased, brown, papillose, centripetal; 
proximal sinus wide, running 1/2 way to valley 
bottom; endocarp slightly supramedian, 2 cm 
long, bony, dark mahogany-colored, the lateral 
walls 1. 3-1.5 mm thick, the inner surfaces 
smooth, shining; seeds 9-11 mm long, ellipsoid; 
upper mesocarp forming in the apex of each 
carpel a cavern with an aerenchyma of white 
membranes and a few fibers; basal mesocarp 
fibrous and fleshy. 
HOLOTYPUS: Indonesia, Anamba Islands, Pa- 
dang, near Letong, Jemoja, sea level, 12 April 
1928, M. R. Henderson 20,365 (SING). Isotypes 
(BO, K)! 
SPECIMENS EXAMINED: Anamba Islands, 
Tanjong Suka, Siantan, among rocks near sea, 
5 April 1928, M. R. Henderson 20,222 (k, sing). 
DISCUSSION: P. Hendersonii is a member of 
the section Pandanus, as is its closest relative, 
P. rubricoloratus St. John, from Pulau Tioman, 
off the east coast of Malaya. The latter species 
has the syncarp 9 cm long, globose; phalanges 
3.6 cm long, red, the central apical sinuses 0.5-2 
mm deep; endocarp inner surfaces papillose and 
a little shiny; leaves 66-73 cm long, 2.8-3 cm 
wide, at midsection with 27 secondary parallel 
veins in each half and the midrib below with 
prickles 1.5-2 mm long, 6-13 mm apart, P. 
Hendersonii has the syncarp 19 cm long, obo- 
void-ellipsoid; phalanges 4.5-5 cm long, orange- 
red and yellow; central apical sinuses 3-4 mm 
deep; endocarp inner surfaces smooth, shining; 
leaves 1.01-1.53 m long, 4-5 cm wide, at mid- 
section with 38-42 secondary parallel veins in 
each half, and the midrib below with prickles 
2-2.5 mm long, 4-8 mm apart. 
The second collection, Henderson 20,222, is 
identical with the type except for having a 
smaller syncarp with smaller phalanges (about 
3.9 cm long). From their structure and appear- 
ance, this difference is judged to be due to im- 
maturity. 
This new species is named in honor of M. R. 
Henderson, former director of the Singapore 
Botanic Garden. 
