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The Cycad Pages
Cycas micholitzii

Cycas micholitzii Dyer, "Gard. Chron. 38: 142-144, figs 48-49" (1905).
"TYPE: Vietnam, ""Annam"", Micholitz s.n. (holo K, 4 sheets)."


Etymology: Honouring W Micholitz (1854-1932), who made the type collections. Micholitz was a plant and insect collector who collected extensively in Asia and New Guinea, employed for many years by English plant merchants Sander & Sons.

Literature: Leandri 1931, Ho & Duong 1960, Smitinand 1971.

Illustrations: Thiselton-Dyer 1905, Prain 1909, Raffill 1912, Smitinand 1971.

Historical notes: This remarkable species was described by English botanist Sir William Thiselton-Dyer in 1905. Material apparently collected by Micholitz in Annam (northern Vietnam), came into possession of Henry Ridley, Director of Singapore Botanic Gardens, in 1904. He proposed that it should be the type of a new genus (in correspondence to Thiselton-Dyer). Thiselton-Dyer received material of Micholitz's collections from Sander & Sons in 1905, and from Ridley (including botanical drawings by an artist on Ridley's staff) at about the same time. He astutely recognized that this species belonged with the genus Cycas, despite the unusual leaf. He described it as a new species in 1905, noting the similarities with the specimen he had earlier described as C. rumphii var. bifida but not combining the two. Subsequent authors until now have combined the two, although closer inspection in recent times has now shown them to be distinct (see C. bifida).

Quite large numbers of plants were collected by Micholitz and imported to England by Sander and Sons, and the species created considerable interest in European horticultural circles (Prain 1909, anon. 1910, Raffill 1912). Male and female coning was documented at Kew (anon. 1910, Raffil 1912), but most of the imported plants were apparently lost in the general decline in interest in exotic ornamental horticulture that followed WW1. The Dublin Botanic Gardens is the only collection known (in 1998) to still have a single plant from these collections.

Distinguishing features: The most immediately striking feature of this species is the dichotomously divided leaflets. However, this also occurs in several related taxa, and in a horticultural form of C. revoluta that is popular in Japan. The subterranean habit, the small, soft microsporangiate cones, the loose, freely peeling sarcotesta lacking a fibrous layer and the verrucose sclerotesta are also all features shared by related species (section Stangerioides). Within this group of related species, C. micholitzii is distinguished by the short leaves with dull, comparatively short and narrow leaflets that are dichotomously divided very near to the base, and small pollen cones with distinct short spines on the microsporophyll tips.

Distribution and habitat: The Annam Highlands region of central Vietnam and eastern Laos, in low, scrubby but fairly dense woodland with substantial seasonal (monsoon) rainfall and additional year-round montane rainfall.

Conservation status: Virtually unknown from the time of Micholitz until the last few years, this species has been severely reduced in numbers both by collecting and by unrestrained agricultural and forestry development. The rarity combined with the unusual habit make it a very highly sought plant by collectors. It is still, however, frequent in many places, and not considered to be immediately at risk. Cycas micholitzii was listed by the 1997 IUCN Red List of Threatened Plants as category E, but this listing refers primarily to the Chinese occurrences now regarded as C. bifida. IUCN (1994) Red List status VU A2c.
Photo Ken Hill

Description:

Stems acaulescent, 10-15 cm diam. at narrowest point; 2-6 leaves in crown.

Leaves bright green, semiglossy or dull, 110-240 cm long, moderately keeled (opposing leaflets inserted at 90-120° on rachis), with 18-56 leaflets, with white tomentum shedding as leaf expands; rachis consistently terminated by paired leaflets. Petiole 50-105 cm long (40-55% of total leaf), petiole glabrous, spinescent for 70-95% of length. Basal leaflets not gradually reducing to spines, 230-330 mm long.

Median leaflets dichotomously branched, strongly discolorous, 230-360 mm long, 11-19 mm wide, inserted at 60° to rachis, narrowed to 2-3 mm at base (to 10-20% of maximum width), 35-60 mm apart on rachis; median leaflets section flat; margins flat; apex softly acuminate, not spinescent; midrib raised above, flat below.

Cataphylls narrowly triangular, soft, pilose, 60-80 mm long, articulated.

Pollen cones narrowly ovoid or fusiform, yellow, 15-25 cm long, 3-5 cm diam.; microsporophyll lamina soft, not dorsiventrally thickened, 13-18 mm long, 7-11 mm wide, apical spine prominent or rudimentary, sharply upturned, 1-6 mm long.

Megasporophylls deeply pectinate.

Seeds ovoid; fibrous layer absent; sclerotesta verrucose. Spongy endocarp absent.


The Cycad Pages

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Written and maintained by Ken Hill 1998-2010
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