台灣植物誌 第二版 Flora of Taiwan, 2nd edition Vol. 1
1. CYCADACEAE 蘇鐵科
SHEN, CHUNG-FU and TSOU, CHIH-HUA
Monogeneric (Cycas), evergreen, dioecious, palm-like trees or shrubs; trunk columnar, covered with persistent woody petiole-bases. Leaves pinnately compound, large, spirally arranged, (0.8-) 1-2 (-3) m long, (15-) 20-30 (-40) cm broad, linear to lanceolate, apex acute or obtuse, rarely emarginate, the basal leaflets often reduced to spines; ptyxis of the whole compound leaf involute with the rachis erect and the pinnae circinate, ptyxis of the first compound leaf circinate (in seedling stage); leaflets numerous but rarely over 200 pairs, long linear to very narrowly lanceolate, (10-) 15-30 (-40) cm long, (3.5-) 5-18 (-25) mm broad, entire with margin slightly thickened or somewhat revolute, single-veined, chartaceous to thick-coriaceous, in C. micholitzii generally (sub) dichotomously branching once or even twice, generally somewhat tapering towards base and then attaching to the rachis decurrently with the lower side generally decurrent to a greater extent, without a clearly-defined petiolule. Male cones shortly peduncled, terminally and generally singly borne, narrowly ovato-cylindric or fusiform; male sporophylls numerous, narrowly wedge-shaped with a somewhat projecting, upward-pointing (when long) apical extension and a somewhat clear abaxial ridge, spirally and tightly arranged along an axis, each with numerous pollen-sacs spread over its lower surface. Female sporophylls numerous, mostly very thick, hard, club-like (in C. rumphii complex) or spade-like, densely yellowish/tawny-tomentose at least when immature, spirally borne on the top of the trunk, in most species leaning together to take a broadly ovoid or peach-shaped "cone-like" appearance in both pre- and post- fertilization stages, but in C. rumphii complex generally loosely arranged throughout their presence, comprising a lower fertile stalk and an upper sterile lamina, the former bearing (1-) 2-4 (-5) ovules along each side of its upper portion, the latter either ovate/rounded and pinnatifid or narrowly rhombic and dentate (in C. rumphii complex); ovules erect, with micropyles directing obliquely upward, nearly globose, broadly elliptic, broadly oblong, or broadly obovate, mostly somewhat compressed, ca. 5-13 mm long, glabrous in most species but densely tomentose in the remaining, in C. rumphii complex half-sunken in a notch that is further encircled by a collar. Seeds drupe-like; envelopes 3-layered in most species but 4-layered in C. Rumphii complex; the two cotyledons generally united at their base to form a tubular sheath; germinating hypogeally.
The genus Cycas is composed of about 30 species. It is geographically centered in the southeastern part of Asia, with a range enclosing Madagascar and its neighboring part of continental Africa, Comoros, S India, Sri Lanka, SE Himalayas, S China, S Japan, N Marianas, Solomons, Samoas, Tonga, Fiji, New Caledonia, and N and NE Australia. Only one species is native to Taiwan (endemic also).
1. CYCAS L. 蘇鐵屬
Characteristics of the family.
Fu, S. H., W. C. Cheng, L. K. Fu & C. J. Chen 1978. Cycas. In: Cheng, W. C. & Fu, L. K. (eds.), Flora Reip. Pop. Sin., Vol. 7, pp. 4-17. Science Press, Beijing. (in Chinese)
Hsu, K. S. & S. Y. Lu 1984. Cycas taiwaniana Carruthers. In: The Rare Plants of Taiwan, pp. 22-23, 146-147. Vacation Press, Taipei. (in Chinese)
Shen, C. F., K. D. Hill, C. H. Tsou & C. H. Chen 1994. Cycas taitungensis C. F. Shen, K. D. Hill, C. H. Tsou & C. J. Chen, sp. Nov. (Cycadaceae), a new name for the widely known cycad species endemic in Taiwan. Bot. Bull. Acad. Sin. 35(2): 133-140.