All Floras      Advanced Search
FOC Vol. 12 Page 302, 303, 327 Login | eFloras Home | Help
FOC | Family List | FOC Vol. 12 | Sterculiaceae

17. Pterospermum Schreber, Gen. Pl. 2: 461. 1791.

翅子树属 chi zi shu shu

Trees or shrubs, stellate velutinous or scurfy and scaly. Leaves simple; stipules linear to palmately fimbriate, sometimes forming nectaries, caducous; petiole short; leaf blade lobed or not, leathery, base often oblique, margin entire or serrate, apex sometimes truncate; juvenile leaves sometimes much larger, petiole long, leaf blade often with peltate base and prominently palmately lobed. Inflorescence axillary, 1-flowered or cymose and 1-5-flowered. Flowers bisexual; epicalyx lobes usually 3, usually distant from calyx, entire, fimbriate, or palmately lobed, rarely absent, caducous. Calyx 5(or 6)-lobed, divided nearly to base, usually spreading to ± reflexed, caducous. Petals 5, white or yellow, often erect. Androgynophore present, very short, glabrous. Stamens 15, in 5 groups of 3 alternating with staminodes; filaments connate into tube, free at top; anthers 2-celled, cells parallel, connective pointed; staminodes 5, filiform, longer and thicker than filaments. Ovary 5-locular; ovules 4-22 per locule; style clavate or filiform; stigma longitudinally 5-grooved. Fruit a schizocarp, cylindric or ovoid, angular or rounded, usually woody, sometimes leathery, dehiscent into 5 loculicidal mericarps when mature. Seeds 2 to many per locule, with long, oblong, membranous wing; endosperm scanty or absent; cotyledons usually plicate, simple. 2n = 38.

Between 18 and 40 species: tropical and subtropical Asia; nine species (five endemic) in China.

Sterculia peltata G. Don (Gen. Hist. 1: 517. 1831), based on material from China, has long petiolate 5-lobed peltate leaves that are abaxially puberulent and adaxially glabrous, and has stems and petioles with a white tomentum. The leaf form is much more suggestive of juvenile material of Pterospermum than a species of Sterculia but the white indumentum is difficult to match with the species known from China.

Key to fruiting material (fruits not known for Pterospermum kingtungense)

1 Capsule 3-6 cm   (2)
+ Capsule 8-15 cm   (5)
2 (1) Capsule apex 3-5 mm, beaked.   2 P. proteus
+ Capsule apex obtuse   (3)
3 (2) Small trees, to 5 m tall; branchlets gray puberulent when young.   5 P. yunnanense
+ Large trees, 20-25 m tall; branchlets yellow-brown pilose or velutinous   (4)
4 (3) Petiole 1-2 cm, leaf blade 7-15 × 3-10 cm; capsule stipe robust, 1-1.5 cm.   8 P. heterophyllum
+ Petiole ca. 0.5 cm, leaf blade 5-9 × 2-3 cm; capsule stipe slender, 3-5 cm.   9 P. lanceifolium
5 (1) Leaf blade 24-34 × 14-29 cm, base not oblique.   1 P. acerifolium
+ Leaf blade 4.5-18 × 1.5-11 cm, base oblique   (6)
6 (5) Leaf blade apex truncate and 3-5-lobed; capsule prominently 5-angled, ca. 12 × 7 cm.   4 P. truncatolobatum
+ Leaf blade apex acuminate or caudate; capsule rounded, 8-10 × ca. 3 cm   (7)
7 (6) Branchlets yellow stellate tomentose when young; capsule glabrous, apex beaked.   6 P. niveum
+ Branchlets shortly gray-white woolly when young; capsule ?hairy, apex acute.   7 P. menglunense

List of Keys

Lower Taxa


Related Objects  
  • Pterospermum.pdf
  • PDF

    Flora of China @
    Browse by
    Advanced Search

    Flora of China Home




     |  eFlora Home |  People Search  |  Help  |  ActKey  |  Hu Cards  |  Glossary  |