Dypsis pustulata

Dypsis (DIP-sis) pustulata (poos-too-LAH-tah)
Madagascar. Photo by Dr. Mijoro Rakotoarinivo/Kew.
Scientific Classification
Genus: Dypsis (DIP-sis) Species: pustulata (poos-too-LAH-tah)
Synonyms
None set.
Native Continent
Africa
Morphology
Habit: Solitary & clustering Leaf type: Pinnate
Culture
Survivability index
Common names
None.

Habitat and Distribution

Endemic to Madagascar. Madagascar - Toliara, Taolagnaro, Iabokoho, Tsitongambarika, Ivohibe. Location:

Madagascar. Photo by Dr. Mijoro Rakotoarinivo/Kew.

Madagascar (-24.532030°N, 47.159843°E) Elevation: 0-499 m. Known only from single locality.

Description

Solitary or clustered palm, to 6 m tall, occasionally with aerial branching. Stem 21–25 mm in diam.; internodes 20–30 mm long, dull brown; leaf scars about 3 mm wide. Leaves about 9 in the crown, held ± erect in a rather lax crown; crownshaft well developed, 20–30 cm long, about 2.1–3.1 cm in diam., mid green; leaf sheath 13–17 cm long, 5.4–6.7 cm wide when opened out, mid green, covered with scattered caducous dark brown scales and with 6–13 or more irregular rounded pustules near the base of the petiole, these green when first emerged, becoming corky and grey with age, pustules up to 1.2 cm wide and standing about 5 mm proud of sheath; leaf to 1.25 m long; petiole about 35 cm long, 8 × 5 mm wide, tapering to 5 × 3 mm at the insertion of the basalmost leaflets, adaxially flattened, bearing scattered caducous dark brown scales; rachis up to 90 cm long, scaly as the petiole; leaflets ca. 14 on each side of the rachis, arranged singly or in groups of 2 or 3, slightly fanned within the groups, dark green, cucullate; basal leaflets 26–30 × 1.3–1.5 cm; mid leaf leaflets 25–32 × 2.8–3.6 cm; apical leaflets 6–9 × 1.2–1.5 cm; all leaflets ending in drip tips to 4 cm long; leaflet surfaces glabrous apart from bands of caducous dark brown scales along margins. Inflorescences interfoliar, branched to 2 orders; peduncle about 30–35 cm long, flattened at the base, about 9 mm wide, distally rounded in cross section, about 4 mm in diam., densely covered with dark brown indumentum; prophyll adnate to peduncle in basal 6–7 mm, free part 2-keeled, tightly sheathing, 15–20 × 1.2 cm, covered with caducous dark brown scales; peduncular bract borne 9 cm above prophyll insertion, similar to prophyll but lacking keels; rachis up to 30 cm long, 4–5 mm in diam. at base with dense dark brown indumentum; first order branches 11–13, the basal 5 or 6 branched to 2nd order; rachillae about 20–22, 9–20 cm long, 1.5–2.5 mm in diam., dull green, covered with dense caducous brown scales; triads about 4 mm apart. Staminate flowers somewhat globular at anthesis, ± bullet-shaped in bud, about 5 mm long, 5 mm wide; sepals rounded, about 1.5 × 1.5 mm, irregularly emarginate, strongly keeled, glabrous; petals 4 × 3 mm, broadly triangular, rather fleshy, white; stamens 6, 3.1 mm long, filaments 1.6 × 1 mm, anthers ± sagittate, 2.1 × 1.5 mm; pistillode pyramidal, about 1 mm high. Immature pistillate flower obovoid, about 3.5 × 2 mm; sepals about 3 × 2 mm; petals ca. 2 × 1.5 mm; staminodes 3, irregular, tooth-like, at one side of the gynoecium; gynoecium ovoid to pyramidal, about 1.5 × 1 mm. Fruit unknown. (Dr's. RAKOTOARINIVO, M. AND J. DRANSFIELD. 2012) Editing by edric.

Dypsis pustulata J. Dransf. & Rakotoarin., sp. nov. Single-stemmed or clustering palm, distinctive in the presence of irregular pustules on the leaf sheaths, the sigmoid leaflets few in number and grouped, the inflorescence branched to 2 orders with staminate flowers at anthesis globose, with whitish petals and sagittate anthers. Type: MADAGASCAR.

This unusual species forms colonies in lowcrown forest on ridge tops. It occurs together with the previous species, D. lilacina, the two species very similar in form. Dypsis saintelucei and Beccariophoenix madagascariensis are also prominent features of the palm flora of these ridge tops. Dypsis pustulata is unlike any other species in the genus because of the consistent presence of the corky pustules on the leaf sheaths of every single individual observed. Pustules were sectioned in the field to investigate whether they are galls, but there was no sign of any animal within the swellings. Developing sheaths within the crownshaft already show the presence of pustules. The nature and function of these pustules is as yet unknown, but developmental material has been collected for further study. (Dr's. RAKOTOARINIVO, M. AND J. DRANSFIELD. 2012)

Culture

Cold Hardiness Zone: 10a

Comments and Curiosities

Etymology: Specific epithet from the Latin for pustules. Conservation Status: Conservation status CR (Critically Endangered) (B2ab(ii,iii,v);D). Known only from the ridge top of Ivohibe forest where the area of occupancy is less than 1 km square and where fewer than 20 clumps are recorded. The forest is quite well preserved at the moment but any disturbance in the future may affect the quality of the habitat and thus the population size. (Dr's. RAKOTOARINIVO, M. AND J. DRANSFIELD. 2012)

A solitary or clustering palm with stems to 5 m tall, about 3 cm diameter. The leaves are rarely more than 8 in the crown, are strongly arcuate and have few distant, sigmoid, grouped dark green leaflets. The most remarkable feature is the leaf sheath, which is covered, towards the sheath mouth, with irregular warty excrescences, a feature observed on all individuals, and not known on any other palm species. The inflorescences are interfoliar, and have few robust long rachillae. Staminate flowers are globular, creamy yellow, relatively large and have six stamens with more or less sagittate anthers. (Dr's. RAKOTOARINIVO, M. AND J. DRANSFIELD. 2012)

This and D. lilacina grow together, intermingled in the undergrowth of ridge-top forest together with D. saintelucei and D. culminis. A newly described species from Mt. Ivohibe in south Madagascar. (Dr's. RAKOTOARINIVO, M. AND J. DRANSFIELD. 2012)