Revision of the Genus Pandanus Stickman, Part 32 
The New Section Involuta from Papua 
Harold St. John 1 
The flora of New Guinea is rich in both the 
number of the species and the sections of 
Pandanus . In the present paper are described 
an additional species and section from that large 
tropical island. 2 
Section Involuta sect. nov. 
(subgen. Lop ho stigma') 
Carpelis separatis 1-loculatis ellipsoideis, stylo 
breviter cylindrico et infra stigmatem bojaris formanti 
deinde involuta prolongato et 2-6 lobis cordatis vel 
flabellatis centralibus supra stigmatem circularem for- 
manti. 
Carpels distinct, 1 -celled, ellipsoid; style 
apical, short cylindric, forming a collar below the 
stigma and at one edge upward produced, in- 
volute, with 2—6 cordate or flabellate horizontal 
lobes, central and above the irregular ring-like 
stigma; staminate plants unknown. 
holotypus: Pandanus involutus St. John. 
discussion: The section also contains P. 
leiophyllus Martelli, of Indonesian New Guinea. 
The name is from the Latin participle, in- 
volutus, infolded, and refers to the structure of 
the style apex. 
Pandanus involutus sp. nov. (sect. Involuta ) 
Figs. 279 and 279A 
diagnosis holotypi: Arbor gracilis ad 12 m alta, 
trunco brevi ex radicibus fulturosis paucissimis 
longioribus salientibus sustentis, foliis 1.19 (+ 0.04 
?) m longis proxima basem 3 cm latis in medio 2.8 
cm latis coriaceis supra viridibus lucidisque infra 
pallidioribus et glaucis LJ-sulcatis 2-plicatis in sectione 
1 B. P. Bishop Museum, Honolulu, Hawaii 96819, 
U. S. A. Manuscript received September 7, 1964. 
2 This can be inserted in the author’s key in Part 
1 of this series (Pacific Sci. l4(3):225), after the 
second I. "Stigma terminal,” insert: 
a. Stigma an irregular ring, partly covered by in- 
volute central cordate or flabellate lobes of the 
style Involuta 
a. Stigma not so, 
medial! cum 48 nervis parallel is secundariis in quo • 
que dimidio nervis tertiis nullis lamina ligulata sed 
in parte % ultima in apice gracili trigono subulate 
sensim diminuenti (sed apice perdito) eo in puncto 
circa 10 cm ex apice 3 mm lato basi inermi pallida 
vel rosacea, ex 2.5 cm marginibus cum aculeis 0. 3-0.7 
mm longis 1.5-3 mm separatis infimis deltoideis 
salientibus turn alteris lancei-deltoideis distal! con- 
cavis sed in toto adscendentibus pallidis, midnervo 
infra ultra mediam inermi, in sectione medial! mar- 
ginibus cum serrulis 0.2-0. 4 mm longis 1-3 mm 
separatis b runnels, in apice subulato marginibus et 
midnervo infra cum crenulis 0. 1-0.2 mm longis 0.3- 
1 mm separatis, syncarpio licet 13-15 cm longis 10- 
10.5 cm diametro licet ovoideis in bracteis siccis 
clausis, nucleo ovoideo in centre mo lie in margine 
membranoso et cum fibris paucis superficie cum 
foramenibus favicis 3-4 mm profundis membranosis 
pallidis, drupis 18-20 mm longis 7-9 mm latis 6-8 
mm crassis oblancei-ellipsoideis parte % supera libera 
obtusa, piieo 7-9 mm alto latiter ovoideo 6-anguloso 
laevi lucido cum 'vicinis adnatis et in laminis caducis, 
stylo osseoso lucido apicali cylindrico 1-1.5 mm alto 
deinde in 2-6 lobis involutis elevatis productis parte 
V 2 -V 3 supera horizontal! irregulariter cordata vel 
.{label lata, stigmate solitario suborbiculari intra bojaris 
inferis et lobis centralibus superb styli, endocarpio in 
parte % infera truncate osseoso obscure brunneo vel 
nigro lateribus lateralibus 1.3-1. 8 mm crassis intra 
laevibus lucidis, semine 9-10 mm longo, mesocarpio 
apicali 3 mm longo oblatiori-orbiculari cavernoso cum 
membranis bmnneis paucis, mesocarpio basali parvo 
fibroso et carnoso. 
diagnosis of HOLQTYPE: Slender free up to 12 
m tall, trunk short, supported on unusually few, 
very long, wide-flung prop roots; leaves 0.93- 
1.19 (+ 0.04 ?) m in length, near the base 3 
cm wide, at the middle 2.8 cm wide, coriaceous, 
green and shiny above, pale green and glaucous 
below, U-sulcate, 2 -pleated, at midsection with 
48 parallel secondary veins in each half, no 
tertiary veins; blade ligulate but in outer 1/4 
gradually tapering into the slender trigonous 
subulate apex (but the small tip lost in ours), 
this at about 10 cm down 3 mm wide, the base 
unarmed, pale or pinkish, beginning at 2.5 cm 
up the margins with prickles 0.3-0. 7 mm long, 
1.5-3 mm apart, the lowest few deltoid, salient, 
532 
