Medusanthera samoensis (Reinecke) R.A.Howard

First published in J. Arnold Arbor. 21: 469 (1940)
This species is accepted
The native range of this species is Samoa. It is a tree and grows primarily in the wet tropical biome.

Descriptions

Utteridge, T.M.A. Kew Bull (2011) 66: 49. https://doi.org/10.1007/s12225-011-9266-z

Type
Type: Samoa, Savai'i, "Vaipouli-Busch", Sept. 1894, Reinecke 72a (lectotype WRSL n.v., designated by Howard (1943b)).
Morphology General Habit
Small tree 4 – 15 m
Morphology General Indumentum
Indumentum of simple appressed hairs, translucent, colourless to pale yellow, 0.05 – 0.2 mm long
Morphology Branches
Branches 2.5 – 5 mm in diameter, densely hairy when young, soon sparsely hairy then glabrous, drying pale olive-green
Morphology Leaves
Leaves on fruiting plants as staminate except 10 – 26.5 × 5.5 – 11 cm, base rounded; petioles 2 – 2.6 cm Leaves on staminate plants: lamina chartaceous, elliptic to oblong, 6 – 15 (–19.5) × 4 – 8 cm, apex attenuate to very shortly acuminate, acumen 4 – 13 mm long, base obtuse-cuneate; ad- and abaxial lamina glabrous, lamina drying olive-green adaxially, pale yellow-green abaxially; midrib ± sulcate and glabrous adaxially, prominent and sparsely hairy or glabrous abaxially; secondary veins brochidodromus, not enclosed by secondary arches, 9 – 10 (– 12) pairs, glabrous, ± prominent ad- and abaxially; tertiary veins very weakly percurrent; petioles 1.1 – 2.2 cm long, densely hairy when young, soon glabrescent
Morphology Reproductive morphology Flowers
Staminate flowers pentamerous, calyx crateriform, 1 – 1.25 mm long, shallowly 5-lobed, glabrous; petals oblong, 4 – 6 × 1.5 – 1.9 mm, glabrous, pale green to white; stamens with anthers 0.9 – 1.6 mm long, filaments narrowly cylindrical, (1.5 –) 3 – 5.2 mm long, white and densely hairy with linear, pale purple, membranous hairs 1.25 – 2.5 mm long on the ad- and abaxial surface of the filaments immediately below the anthers (colours from Whistler 2004); pistillode 1.4 mm long Pistillate flowers not seen
Morphology Reproductive morphology Inflorescences
Pistillate inflorescences as staminate inflorescences except primary axis 3 – 3.5 cm long, branched to the 2nd order only Staminate inflorescences axillary, sometimes fasciculate with up to 3 inflorescences in each axil, umbellate with ultimate branches terminating in a cyme or irregular cyme, primary axis (12 –) 36 – 58 mm long, with 3 first order branches these dichotomously branching to the 3rd order, sparsely hairy; pedicels 2.5 – 3.5 mm long, hairs as the inflorescence branches
Morphology Reproductive morphology Fruits
Fruits oblong, apex rounded, base truncate, glabrous; when dry putamen flattened, not curved, narrowly oblong, 29.5 – 37.8 × 9 – 10.8 mm and 7 – 8.6 mm thick (measurements include only drupe as appendage is not significant when dry), putamen with a central ridge running the length of the convex side of the fruit, with 4 – 8 smaller ridges on either side, pulviniform appendage oblong, 14 – 20 × 4 – 7 mm covering the centre of the concave surface; when fresh drupe creamy white, pulviniform appendage fleshy, pale green maturing pink (colours from Whistler 2004).
Distribution
Endemic to the Samoan islands (American Samoa and Samoa).
Ecology
Lowland to cloud forest, more common at higher elevations (fide Whistler 2004); 60 – 1400 m.
Conservation
This species is only known from 12 localities throughout the Samoan islands. Whistler (2002) discusses the numerous threats to the native vegetation of the Samoan archipelago including both manmade and natural threats, especially population growth. Many of the collections are historical from lowland areas, and examining these localities using satellite imagery shows that these have now been converted to agricultural use (especially on Upolu), or are from forest areas adjacent to areas of habitat conversion. Using satellite imagery to measure the maximum AOO (c. 1,590 km2) in the islands by estimating cover of forest-type habitats (rather than urban and agricultural land) — rather than EOO (because of the sea being unsuitable habitat for the species) — together with the continuing loss of habitat on the islands and its distribution in only four locations, suggests a rating of Vulnerable (VU 2ab(ii,iii)).
Vernacular
Mātamō (Howard 1943a, b; Whistler 2004) and tofiga (Howard 1943a, b) have been reported as the Samoan names.
Note
This species is distinct because of the large leaves, especially on the female (fruiting) plants, which can be up to 26.5 cm long on petioles (usually 1 – 2.6 cm long) and especially the narrowly oblong drupe which is relatively large reaching up to nearly 4 cm long with a fleshy appendage which matures pink. The flowers and fruits, in vivo, are illustrated in Whistler (2004). There are no other Medusanthera species on Samoa but this species is similar to M. vitiensis, particularly with regard to the sexual dimorphism of the plants. M. samoensis differs from M. vitiensis in the leaf size, with both male and female plants having larger leaves (M. samoensis: leaves on female plants 10 – 26.5 cm long; M. vitiensis: 8 – 14.9 cm long), the longer petioles (M. samoensis: petioles on female plants 2 – 2.6 cm long; M. vitiensis: 0.9 – 1.9 cm long), and, especially in the drupe, which is narrowly oblong with a rounded apex (M. vitiensis drupe narrowly triangular with an attenuate apex); also note that the fleshy appendage in M. vitiensis has been recorded as maturing to a white colour.
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Uses

Use
"The wood is sometimes used for posts and house parts, but the plant is known by few people today" (Whistler 2004).
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Sources

  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2023. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2022 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0
  • Kew Bulletin

    • Kew Bulletin
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2023. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2022 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0