6. Pothos macrocephalus
Scort. ex Hook.f.
Scort. ex Hook.f., Fl. Brit. Ind. 6 (1893) 553; Engl. in Engl.,
Pflanzenr. 21 (IV.23B) (1905) 31. Syntypes: Malaysia, Perak,
Scortechini 116b (K!); Malaysia, Perak, Larut, Goping, Kunstler
(Dr Kings collector) 492 (K!); Malaysia, Perak,
Larut, Goping, Kunstler (Dr Kings collector) 4327
(K!); Malaysia, Perak, Larut, Goping, Kunstler (Dr Kings
collector) 6029 (K!).
Large, robust homeophyllous root-climbing liane to 15 m. Eocaul
not observed; stem of juvenile shoot to 8 mm diam., weakly angled
or subterete in cross section, leaves scattered or congested; stem
of mature sterile shoot to 12 mm diam., mid-green, later turning
brown, air-drying black-brown weakly four-angled, at first somewhat
densely clothed with leaves, early growth often with all leaves
directed forwards and the whole appearing imbricated, later with
leaves distichous, spreading, stems eventually becoming naked, naked
portions with prominent 60 80 mm distant nodes; stem of fertile
shoot to 5 mm diam., terete to weakly to somewhat prominently angled
in cross section, the angles occasionally minutely winged, mostly
densely clothed with leaves, older portions naked for approximately
half their length, naked portions with prominent nodes to 30 mm
distant. Leaves when fresh bright to mid-green adaxially, paler
abaxially, air drying dull green to brownish; petiole 50
140 x 5 15 mm, broadly winged, oblong to obovate-oblong,
with 4 5 secondary veins per side, base decurrent to clawed,
apex truncate, rounded or auriculate; lamina 3 180 x 15
c. 205 mm, ovate to elliptic or lanceolate with 2 4 intramarginal
veins per side, these arising from the base and either immediately
diverging or remaining very close and parallel to midrib and then
diverging further along lamina, either reaching the leaf tip or
merging into a prominent submarginal collecting vein, additional
veins arising obliquely from the midrib, remaining parallel with
numerous veins arising from them, base rounded to acute, apex attenuate-mucronate
to acute or attenuate, minutely tubulate. Flowering shoot much abbreviated,
arising from mostly the middle to distal leaf axils of fertile shoots,
sometimes arising on older (foliage) leafless parts, bearing a minute
prophyll and a few 5 35 mm, sequentially longer cataphylls.
Inflorescence solitary; peduncle 40 100 x 1.5 2 mm,
rather stout, erect, dull orange-yellow; spathe 4 12 x 4
10 mm, ovate, flat to convex, base cordate, clasping the
peduncle, apex slightly raised, acute to subacute with a stout mucro,
white, somewhat waxy; spadix stipitate; stipe 27.5 40 x 2
2.5 mm, terete in cross section, erect, straight, pale green;
fertile portion 12.5 15 x 10 12 mm, ovoid-clavate,
mid-yellow. Flowers c. 1 2 mm diam.; tepals 1 x 0.3 mm, oblong-cymbiform,
apex fornicate, triangular, truncate; stamens 1 4 x c. 0.5
mm, filaments strap-shaped, thecae c. 0.2 mm diam., yellow; ovary
1 1.5 x 0.25 0.75 mm, compressed angular-ellipsoid,
yellow; stylar region truncate; stigma punctiform. Infructescence
with 1 5 berries; fruit obclavate to ovoid or ellipsoid,
10 17.5 x 10 14 mm, deep green ripening to scarlet,
epidermis of upper part of ovary roughened in submature fruits,
more or less smooth when ripe. Seeds c. 3 6 mm diam., ellipsoid
Distribution Indonesia (Sumatera), Peninsular Malaysia,
Habitat & Ecology Rain forest on granitic rock
along stream. 50 300 m.
Note A large distinctive climber which, for the area
under review, has so far been collected only in Yala and Narathiwat
provinces of peninsular Thailand where its occurrence is sporadic.
The large yellow-and-white inflorescences are most similar in appearance
to those of P. gigantipes.
However, the form of the mature and juvenile leaves of these species
is quite different (compare Figs 6, 6a with 3, 3a). Sterile P.
macrocephalus can be confused with P.
scandens although in the latter the petiole is generally
shorter than the lamina and overall P. macrocephalus
is a more massive plant.
Geographically representative selection of collections studied:
THAILAND. PEN75. Yala: Than Tio, 006° 20N, 101° 20E,
25 April 1974, Geesink & Hattink 6437 (fl., fr.) (BKF, K, L).
PEN76. Narathiwat: Sungei Kolok, Nikom Waeng, 005° 50N,
101° 50E, 1 March 1974, Larsen & Larsen 32765 (fl.)
(AAU, BKF, K, L, P).