534 
PACIFIC SCIENCE, Vol. XXII, October 1968 
Fig. 279A. Pandanus involutus St. John. Habit 
view of holotype. 
then the succeeding ones lance-deltoid, the 
outer edge concave, but the whole ascending, 
pale; the midrib below unarmed to well beyond 
the middle; at midsection the margins with serra- 
tions 0. 2-0.4 mm long, 1-3 mm apart, brown; 
on the subulate apex the margins and midrib 
below with crenulations 0.1-0. 2 mm long, 0.3- 
1 mm apart; infructescence with a solitary syn- 
carp, erect among the leaves; peduncle 18 mm 
in diameter at apex, more than 7 cm long, 
clavate, 3-sided, with crowded, deciduous bracts; 
syncarp apparently about 12.5 cm long, it is 
10-10.5 cm in diameter, ellipsoid, enclosed in 
dry, brown bracts, these in 3 ascending tiers, 
each of 4-6 imbricate bracts, the outermost one 
with the body 21 cm long, 8 cm wide, lanceo- 
late, the linear tip lost; the 3-4 inner bracts in 
each tier subequal, 14-15 cm long, 10-12 cm 
wide, ovate, acute, the upper margins and mid- 
rib minutely prickly; core ovoid, the whole cen- 
ter of soft, evanescent tissue, the margin of 
membranes and a few fibers, the outer surface 
pocked by honeycomb-like sockets (for the 
drupe bases), 3-4 mm deep, of pale membra- 
nous tissue; drupes 18-20 mm long, 7-9 mm 
wide, 6-8 mm thick, oblance-ellipsoid, 6-angled, 
upper y 3 free, obtuse; pileus 7-9 mm high, 
broadly ovoid, 6-angled, smooth, shining, the 
adjacent ones adnate and dehiscing in sheets; 
style bony, shining, apical, forming a stout 
cylinder 1-1.5 mm high which then is pro- 
duced into 2-6 involute raised lobes, their up- 
per portions horizontal, irregularly cordate or 
flabellate and occupying !/ 2 -% of the truncate 
stigmatic apparatus; stigma solitary, but occur- 
ring as the marginal part of the apical disk, 3- 
4.5 mm in diameter, more or less circular, but 
of irregular shape, filling the interval between 
the collar of the lower part of the style and its 
involuted expanded central lobes; endocarp in 
lower %, obovoid, truncate, bony, dark brown 
to black, the lateral walls 1.3-1. 8 mm thick, 
within smooth, shining; seed 9-10 mm long; 
apical mesocarp 3 mm long, very oblate orbi- 
cular, a cavern with a few brownish membranes ; 
basal mesocarp scant, fibrous and fleshy. 
holotypus: Papua. Rossel I., Abaleti, com- 
mon in rain forest of the ridges, 20 m alt, Oct. 
8, 1956, L. J. Brass 28,366 (k). Isotypes (a, 
l, us) ! 
discussion: The only close relative of this 
species is P. leiophyllus Martelli, from Windesi, 
Geelvink Bay, Indonesian New Guinea, a spe- 
cies with the drupes with the upper y 6 free; 
pileus 4-5 mm high, rounded convex, broadly 
retuse, and many with hornlike, lateral ascend- 
ing processes; stigma with one broad invagina- 
tion at the sinus and slight hints of others 
around the margin; endocarp walls 0.7-0. 8 mm 
thick; leaves 3.4-3. 5 cm wide, the secondary 
parallel veins 42-46 in each half at midsection, 
the tertiary cross veins seen below in outer I/4, 
oblique, forming narrow rhombic meshes. P. 
involutus has the drupes with the upper I/3 
free; pileus 7-9 mm high, broadly ovoid, not 
horned; stigma with 2-6 prominent stylar in- 
vaginations; endocarp walls 1.3-1. 8 mm thick; 
leaves 3 cm wide, at midsection with 48 parallel 
secondary veins in each half, the tertiary veins 
none. 
In 1913-1914, in the same book, Martelli 
