Dypsis humilis
Dypsis (DIP-sis) humilis (hoo-MIHL-iss) | |||||||
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Makira; Protected Area, Madagascar. Photo by Dr. John Dransfield, Royal Botanic Gardens, Kew/Palmweb. | |||||||
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Contents
Habitat and Distribution
Northeast Madagascar, known from a single site above the Antainambalana River near the village of Ambodivoahangy west-northwest of Maroantsetra. Disturbed rain forest on granitic ridge top, alt. 100-200 m.Description
Dypsis humilis is a low growing palm with no visible stem ("acaulescent"), and approximately eight leaves sprouting from the ground—described as looking "like a shuttlecock". The leaves are approximately 80 cm (31 in) long, with about sixteen leathery leaflets on each leaf. The inflorescences are inconspicuous, from 22 to 35 cm (8.7 to 14 in) long, growing at the base of the plant amidst the leaves. The pistilate flowers are 2.5 mm (0.098 in) by 1 mm (0.039 in), with sickle-shaped fruits that are approximately 1.8 mm (0.071 in) long and .3 mm (0.012 in) wide. The species is quite distinct from other Dypsis species in Madagascar, with only two other acaulescent species previously recorded—both of which have very different leaves and habitat. Editing by edric.
Clustering, acaulescent palm.
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Leaves 8 in the crown; petiole about 40 cm long, 3-4 mm wide, densely black/brown scaly, adaxially flat; leaf rachis about 40 cm long, in mid-leaf 1.2-2 mm wide, pubescent/scaly; leaflets sigmoid, 8 on each side of the rachis, borne regularly, inserted 1-5 cm apart, proximal leaflets 22-27 × 2-3 cm, with 2-3 folds, median leaflets 20-23 × about 2 cm, single fold, distal leaflets 10-14 × 2-3.5 cm, with 3-5 folds, abaxial surface sparsely brown scaly, distal margins of leaflets densely scaly, medifixed ramenta on abaxial surface of mid-veins in proximal half of leaflets, 0.1-0.4 mm long. Inflorescence 22-35cm long, interfoliar, branched to 1 order, erect; peduncle 10-15 cm long, 0.5-2 mm wide, pubescent; prophyll 6-7 cm long, 0.5-1 cm wide, 2-keeled, opening apically; Peduncular bracts 2; first peduncular bract similar to prophyll, 11-13 cm long, 0.5-1 cm wide, borne 4 cm above the insertion of the prophyll, opening apically; second peduncular bract triangular, not enclosing the peduncle, 0.2-0.4 cm long; rachis about 15 cm long, pubescent, with 4-6 rachillae; rachillae to 14 cm long, 0.8-1.4 mm in diam., 0.5-1 cm apart; sparsely pubescent, triads 2-4 mm apart, arranged spirally. Staminate flowers 1.5 × 1.1mm, sepals 3, 0.7 mm long, petals 3, valvate, 1.5 × 0.9 mm, stamens 6, filament 0.5-0.7 × 0.2-0.3 mm, flattened, anthers 0.3 × 0.2 mm; pistillode 0.3 × 0.2 mm. Pistillate flowers 2.5 × 1.5 mm, sepals 3, petals 3, valvate, triangular, 2.1 × 1.3 mm, gynoecium gibbous, 1.3 × 1.2 mm, stigmas 3. Fruits immature, green, sickle shaped, 1.8 × 0.3 mm. Seeds immature, about 3 × 11 mm, endosperm homogeneous. (M. Rakotoarinivo, M.S.Trudgen and W.J.Baker. 2009)/Palmweb. In reproductive morphology, this new species appears most similar to taxa in Dypsis Group 8 (e.g. D. concinna, D. corniculata, D. thiryana) of Dransfield and Beentje (1995) or perhaps Group 5 (D. procumbens). However, neither of these groups contains acaulescent species. In fact, only two other species of acaulescent Dypsis have been recorded from Madagascar. They were poorly known when The Palms of Madagascar (Dransfield & Beentje 1995) was published, but both have since been rediscovered (Dransfield et al. 2006). Neither can be confused with D. humilis. Dypsis acaulis (Group 18) from Masoala is a stemless or very short palm with bifid leaves that are chalky white on the undersurface, spicate inflorescences and staminate flowers with three antepetalous stamens. Dypsis aquatilis (Group 16), known from one locality in Manantenina in southeast Madagascar, is truly acaulescent and grows in water. It is more robust than D. humilis with very different leaf characteristics and has inflorescences branched to two orders. Dypsis humilis is thus a very distinct and easily. (M. Rakotoarinivo, M.S.Trudgen and W.J.Baker. 2009)/Palmweb. |
Culture
Cold Hardiness Zone: 10a
Comments and Curiosities
Conservation: Critically endangered [CR (A1 + D)] (provisional assessment). Known only from one locality where fewer than ten individuals were observed. The site is outside the boundary of the Makira protected area and the forest is degraded (M. Rakotoarinivo, M.S.Trudgen and W.J.Baker. 2009)/Palmweb.
The plant is provisionally listed as Critically Endangered, the highest risk category for wild plants, by the IUCN Red List. The only known plants are in an unprotected area just outside of Makira Natural Park, so the species' survival is not very secure.[1] Madagascar has less than 10% of its native vegetation intact, with an additional 200,000-300,000 hectares of forest lost each year. Out of 172 Madagascar palm species known in 2007, only 18 are not threatened by habitat loss, with many on the edge of extinction.
Dypsis humilis grows in northeast Madagascar, near the Antainambalana River, outside of Maroantsetra, a seaport town on the Bay of Antongil. It is found in rainforest on a granitic ridge top between 100 to 200 m (330 to 660 ft) elevation. Less than ten plants were seen, in an area of forest disturbed by human activity, including logging.
External Links
- Glossary of Palm Terms
- MODERN BOTANICAL LATIN
- "Just To Be Clear"
- https://www.palms.org/palmsjournal/2009/v53n3p125-146.pdf
References
Phonetic spelling of Latin names by edric.
Special thanks to Geoff Stein, (Palmbob) for his hundreds of photos.
Special thanks to Palmweb.org, Dr. John Dransfield, Dr. Bill Baker & team, for their volumes of information and photos.
Glossary of Palm Terms; Based on the glossary in Dransfield, J., N.W. Uhl, C.B. Asmussen-Lange, W.J. Baker, M.M. Harley & C.E. Lewis. 2008. Genera Palmarum - Evolution and Classification of the Palms. Royal Botanic Gardens, Kew. All images copyright of the artists and photographers (see images for credits).
M. Rakotoarinivo, M.S.Trudgen & W.J.Baker. 2009. The Palms of the Makira Protected Area, Madagascar.
Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.