The Cycad Pages
Cycas revoluta

Cycas revoluta Thunb., "Verh. Holl. Maatsch. Weetensch. Haarlem 20(2): 424, 426-427" (1782). H—UPS
TYPE: ex herb. Thunberg (lecto (fide Stevenson & Hill) UPS 23734).

Cycas revoluta var. brevifrons Miq., Tijdschr. Wis-Natuurk. Wetensch. Eerste Kl. Kon. Ned. Inst. Wetensch. 1: 207 (1848).

TYPE: See Photos of U & L.
Cycas revoluta var. planifolia Miq., Monogr. Cycad.: 25-26 (1842).
"TYPE: Hort. Amsterdam, 1840, Miquel s.n. (holo U)."
Cycas revoluta var. prolifera Siebold & Zucc., Abh. Math.-Physik. Cl. Konigl. Bayer. Akad. Wiss. 14(3): 236 (1846).
TYPE: from Garden Material (?).
Cycas revoluta var. robusta Messeri, "Nuovo Giorn. Bot. Ital., n.s., 34: 324, 327" (1927).
"TYPE: Cultivated in Firenze. Also, should this read ""Messeri ex J. Schust."", Pflanzenr. etc? (?)."

Etymology: Latin revolutus, rolled, from the rolled leaf margins.

Literature: Gaudichaud 1829, Merrill 1912, Merrill 1917, Merrill 1923, Leandri 1931, Ho & Duong 1960, Raizada & Sahni 1960, Smitinand 1971, Smitinand 1972, Walker 1976, Zamora & Co 1986, Wang 1996.

Illustrations: Smith 1801, Bot. Mag. 1830, Miquel 1842, Warburg 1900, Schuster 1932, Smitinand 1971, Cheng, Fu & Cheng 1975, Walker 1976, Zamora & Co 1986, Wang 1996.

Historical notes: C. revoluta was the second species of Cycas to be recognised, described in 1782 by Swedish botanist and physician Carl Peter Thunberg. No type was cited. The `Tessio' of both Kaempfer (1712: V,897) and Rumphius (1749: I,70,t.24) were included as synonyms (Thunberg 1784). Reference was also made to cultivated plants, which were probably collected by Thunberg in Japan in 1775-1776, specimens now in UPS. Of the three sheets of C. revoluta present in the Thunberg herbarium, this sheet was chosen as lectotype because it was the only sheet annotated `e Japonia'.

Distinguishing features: Readily distinguished by the keeled, stiff leaves with crowded, stiff, narrow leaflets with strongly recurved or revolute margins and the tomentose ovules.

Distribution and habitat: Widely distributed through the Ryukyu Islands of southern Japan, today primarily on steep to precipitous stony sites, but previously on flatter land now cleared. Reports of natural occurrences in coastal Fukien Province of China have not been substantiated, although circumstantial support for these claims is strong.

Conservation status: A number of natural stands are in protected areas, and this species is in cultivation worldwide in vast numbers, from artificially propagated sources. No immediate threat is evident, and this species is not considered to be at risk (IUCN Red List category LR,nt).


Stems arborescent, to 1-3(-7) m tall, 20 cm diam. at narrowest point.

Leaves deep green, semiglossy, 50-150 cm long, strongly to moderately keeled (opposing leaflets inserted at 70-120° on rachis), with 100-240 leaflets, with orange tomentum shedding as leaf expands; rachis usually terminated by a spine. Petiole 6-10 cm long, spinescent for 80-100% of length. Basal leaflets gradually reducing to spines, 10-20 mm long.

Median leaflets simple, strongly discolorous, 80-180 mm long, 3-6 mm wide, 2.5-5 mm apart on rachis; section slightly keeled; margins revolute; apex aristate, spinescent; midrib flat above, raised below.

Cataphylls linear, pungent, densely floccose, persistent.

Pollen cones fusiform, yellow, 30-60 cm long, 8-16 cm diam.; microsporophyll lamina waxy, not dorsiventrally thickened, 23-28 mm long, 5.5-10 mm wide, apical spine absent, apex deflexed, 4.5-8 mm long.

Megasporophylls 12-19 cm long, yellow-tomentose; ovules 2-6, pubescent; lamina orbicular, 50-120 mm long, 40-55 mm wide, deeply pectinate, with 13-27 soft lateral spines 20-28 mm long, apical spine distinct or not distinct from lateral spines, 30-50 mm long.

Seeds ovoid, 25 mm long, 20 mm wide; sarcotesta red, slightly pruinose; fibrous layer absent; sclerotesta smooth, or longitudinally grooved. Spongy endocarp absent.

The Cycad Pages

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Written and maintained by Ken Hill 1998-2010
Maintained by Leonie Stanberg and Dennis Stevenson 2010-2012
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