{From: A Manual of the Dipterocarp Trees of Brunei State and Sarawak: Supplement by P.S. Ashton, M.A., PH.D., F.L.S.  Borneo Literature Bureau, for the Forest Department, Kuching, 1968.]


Field diagnostic characters.  Lamina resembling that of S. obscura and S. atrinervosa, but 14-24 × 6-15 cm., larger, without cream lepidote undersurface, and with 11-15 pairs of nerves; petiole glabrescent.


Field description.  Large tree,—60 m. tall, —4 m. girth.  Bole tall, straight, cylindrical.  Buttresses —4 m. tall, —3 m. long, c. 10 cm thick, relatively stout, prominent, concave.  Crown  irregularly hemispherical, with a few large ascending twisted branches.  Bark surface  grey-brown, coming away in large irregular flakes.  Inner bark  c. 8 mm. thick, yellow-brown.  Sapwood  reddish brown, hard.  Dammar  not recorded.


Economy.  An important Selangan batu on igneous rock areas in W. Sarawak.


Distribution.  W. Sarawak, locally frequent in Mixed Dipterocarp forest—650 m. alt. on the granodiorite mountains of Lundu, on andesite extrusions at Santubong, porphyry dykes and plugs in the Bau limestone, and in restricted areas on the slopes of Matang.


Sarawak collections.  S. 15482 (Anderson) Bt. Seburan, Bau;  S. 15502 (Anderson et al.) Gt. Gebong;  S. 15396 (Anderson et al.) G. Lundu;  SA. 587 (Baharol), S. 59 (Browne), S. 10172, 7984, 7968 (Bojeng), s.n. (Anderson) Gunong Gading F.R.


Herbarium description.  Twigs and buds shortly evenly fugaceous buff pubescent; leaves glabrous.  Twig  c. 3 × 2 mm. diam. apically, at first compressed, black, somewhat lustrous; internodes 1-3.5 cm. long; stipule scars c. 3 mm. long, pale, prominent, ascending.  Leaf bud —5 × 3 mm., ovoid, acute, black.  Stipules unknown.  Lamina 14-25 × 6-15 cm. large, more or less broadly ovate to elliptic, with broadly cuneate to subcordate base, tapering to the —1 cm. long acumen; nerves 11-15 pairs, obscure above, prominent below, set at 40°-55 to the midrib, intercostals sinuate, closely scalariform; midrib hardly elevated above, prominently so below.  Petiole  2-3.5 cm. long, c. 2 mm. diam., stout, drying black.  Lamina drying uniform dull yellowish brown on both surfaces.  Flowers.  Raceme—12 cm. long,—2 mm. diam. at base (in fruit), terminal or axillary, subterete, densely shortly tufted buff pubescent, singly or doubly branched, branchlets—3 cm. long; bracteoles—4  2 mm., ovate, densely shortly pubescent, fugaceous.  Flowers secund; bud—10 « 3 mm., narrowly ovoid, with the calyx somewhat spreading.   Calyx sericeous in parts exposed in bud; sepals narrowly ovate, subacute, the inner 2 smaller, relatively broader, than the outer 3.  Corolla pale cream; petals linear, densely pubescent on parts exposed in bud.  Stamens  47-52; filaments compressed, tapering, glabrous, anthers oblong, tapering distally, glabrous; appendage to connective exceeding length of anther, densely setose.  Ovary and stylopodium pyriform, densely pubescent, crowned by a glabrous columnar style.  Fruit.  Mature fruit unknown.  Pedicel and calyx, and nut sparsely shortly pubescent at first; fruit calyx lobes unequal, 3 long and two short, spatulate, subacute.  Nut with c. 1 mm. long short apiculus.  Sapling lamina as in mature tree, but less coriaceous.


Regneration.  Abundant.