Oaks of the World

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  Quercus helferiana
Author A.DC 1864 Prodr. 16(2): 101
Synonyms Cyclobalanopsis helferiana ( A.DC) Oersted 1867
ilex Lour. 1790 nom. illeg.
prainiana H.Lév. 1913
Local names mao zhi qing gang
Range India; Laos; Thailand; Vietnam; Myanmar; China (Guangdong, Guangxi, South Guizhou, South Yunnan); 900 to 2000 m;
Growth habit reaches 20 m tall, but often stunted in exposed sites; trunk reaches 1 m in circumference;
Leaves 12-20 x 4-9 cm; evergreen; sub-elliptic or oval-lanceolate; young leaves densely tomentose; apex acuminate to obtuse, base rounded or broadly cuneate; margin crenate in the apical half; adaxially smooth, shiny, glabrous except at the base of the midrib; grey brown tomentose beneath, with persistent fasciate hairs; midvein impressed adaxially; 9-14 vein pairs, raised below, slightly impressed above ; stout petiole 1-2(-3) cm long, pale brown tomentose, glabrescent;
Flowers March-April; female on many-flowered spikes as long as the petiole; 5-6 short styles, staminodes sometimes present;
Fruits acorn flattened 1-1.6 cm long, 1.5-2.2 cm wide; mucronate; flat or sometimes depressed, 1.2-1.4 cm wide basal scar ; enclosed 1/2 by cup; cup flat (5-6 mm long, 2-2.5 cm wide) and thick (1.2-2 mm), with 8-10 concentric rings of minutely, golden tomentose scales, remotely denticulate; maturing in 1 year;

Bark, twigs and

bark very rough, brown, with thick ridges; young twigs rusty tomentose, becoming glabrous when 3 years old; bud hairy, obovoid;
Hardiness zone, habitat not hardy; tropical forests;
Miscellaneous -- A. Camus : tome 1, p. 336, n° 68;
-- Sub-genus Cerris, Section Cyclobalanopsis;
-- Section Helferiana, sub-section Helferianae (Menitsky);

Subspecies and