A synoptic account of the Fagaceae of Thailand

A SYNOPTIC ACCOUNT OF THE FAGACEAE OF THAILAND (C. PHENGKLAI) 55
Evergreen trees, rarely shrubs. Branchlets initially densely yellowish brownpubescent.
Terminal buds ovoid to ellipsoid, scales ovate to linear. Stipules extrapetiolar,
caducous. Leaves spiral, entire or serrate, rarely lobed, glabrous or sparsely hairy unless
along nerves on lower surface and then petioles much swollen near base and always
geniculate. Inflorescences male and female separate or female below and male on the upper
part in some erect spikes, occasionally mixed, densely stellate pubescent including bracts
and bracteoles. Male inflorescences simple and axillary or much-branched and subterminal.
Flowers solitary or in clusters of 3 or more, with one or more small bracts; perianth
campanulate or cup-shaped, usually 6-lobed, free or minutely connate near base. Stamens
12, occasionally fewer, glabrous, anthers dorsifixed. Rudimentary ovary subglobose, villous
or with several villous scales. Female, androgynous or mixed inflorescences solitary in the
axil or in the upper part of a paniculate cluster with males. Flowers solitary or in clusters of
three or more, perianth bracts and bracteoles as in male but smaller. Staminodes 10-12.
Styles 3, occasionally 4, cylindrical, hairy at the base; stigmas terminal and punctiform.
Ripe cupule completely enclosing the one to four nuts, often dehiscent, covered by whorls
of simple or branched spines or tubercles, or with entire rings when it is distinctly oblique.
Fruits ovoid or rounded with the adjoining sides flattened; scar present.
A genus of about 120 species, widely distributed in the subtropical and tropical
parts of South Asia, almost to Australia, and with a divergent distribution in the South-
Western United States of America; 33 species are indigenous to Thailand.
KEY TO THE SPECIES
(based on vegetative characters and acorns)
1. Cupules covered with thin imbricate scales on outer part or smooth. Nuts simple, ovoid or occasionally
depressed
2. Cupules smooth, without scales, only 3–4 undulate lines on outer part, cupule enclosing nut
completely except for the apical umbo. Acorns pyriform. Nuts ovoid 24. C. piriformis
2. Cupules with thin imbricate scales, lamellate
3. Leaves serrate
4. Scales acute and erect at apex. Cupules enclosing up to half of the nut
5. Fruit rachis up to 10 cm long. Petioles usually with one gland on the upper side
13. C. fissa
5. Fruit rachis not less than 15 cm long. Petioles without gland 6. C. calathiformis
4. Scales truncate at apex. Cupules enclosing three-quarters of the nut
6. Scar at base of nut flat. Leaves glabrous 7. C. cerebrina
6. Scar at base of nut curved. Leaves tomentose on lower surface, glabrescent
30. C. siamensis
3. Leaves entire. Cupules enclosing nut completely except the apical umbo, skin of mature acorn
with only 4–5 undulate lines 19. C. lanceifolia
1. Cupules covered with spines or tubercles. Nuts solitary or up to 4, ovoid or flattened to one
longitudinal side, occasionally depressed
7. Cupules with branched or branched and simple spines
8. Cupules with both branched and simple spines, spines hairy, glabrescent
9. Nut solitary in each cupule
10. Nuts curved to one side, apex and base close together, but globose in outline
11. C. echidnocarpa
10. Nuts ovoid, regular 3. C. argyrophylla
9. Nuts (1–)2–4 in each cupule
11. Cupule densely covered with brittle, straight and hairy spines. Cupule more or less
indehiscent when dry 16. C. hystrix