|The Cycad Pages
- 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).
Cycas revoluta var. planifolia Miq., Monogr. Cycad.: 25-26 (1842).
- TYPE: See Photos of U & L.
Cycas revoluta var. prolifera Siebold & Zucc., Abh. Math.-Physik. Cl. Konigl. Bayer. Akad. Wiss. 14(3): 236 (1846).
- "TYPE: Hort. Amsterdam, 1840, Miquel s.n. (holo U)."
Cycas revoluta var. robusta Messeri, "Nuovo Giorn. Bot. Ital., n.s., 34: 324, 327" (1927).
- TYPE: from Garden Material (?).
- "TYPE: Cultivated in Firenze. Also, should this read ""Messeri ex J. Schust."", Pflanzenr. etc? (?)."
Latin revolutus, rolled, from the rolled leaf margins.
Ho & Duong 1960,
Raizada & Sahni 1960,
Zamora & Co 1986,
Bot. Mag. 1830,
Cheng, Fu & Cheng 1975,
Zamora & Co 1986,
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
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'.
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.
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.