Calamus acaulis A.J.Hend., N.K.Ban & N.Q.Dung, Palms (1999+) 52(4). 2008

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Distribution

Map uses TDWG level 3 distributions (http://www.nhm.ac.uk/hosted_sites/tdwg/geogrphy.html)
Vietnam
Known only from Phu Yen in central Vietnam, on steep rocky slopes in disturbed forest. (Henderson, A.J., Ban, N.K. & Dung, N.Q., New species of Calamus (Palmae) from Vietnam in Palms (1999+) 52(4). 2008)A

Discussion

  • The specimens cited here will key in Evans et al. (2002) to Calamus acanthophyllus Becc. Calamus acaulis differs from that species in its prominent, densely brown bristly (versus obscure, non-bristly) ocreas; apical pair of pinnae joined for almost their entire length (versus not joined); and pinnae with minutely bristly margins and non-bristly veins (versus conspicuously bristly margins and veins). However, the short, green stem observed on one specimen of C. acaulis indicates that a taller stem could develop. If this were the case, it would key to C. thysanolepis Hance. It differs from that species in its solitary (versus clustered) stems and apical pair of pinnae joined for almost their entire length (versus not joined). The staminate flowers of C. acaulis appear not to be always distichously arranged, but sometimes in groups. Unfortunately the staminate inflorescence is too old to observe this easily. By its non-climbing habit, eflagellate sheaths, ecirrate leaves, eflagellate inflorescences, and non-pedicellate floral bracteoles, Calamus acaulis appears to belong to Beccari's (1908) Group II. Another non-climbing Vietnamese species is included in this group - Calamus dongnaiensis Pierre. Calamus acaulis differs from this in its solitary (versus clustered) stems and apical pair of pinnae joined for almost their entire length (versus not joined). (Henderson, A.J., Ban, N.K. & Dung, N.Q., New species of Calamus (Palmae) from Vietnam in Palms (1999+) 52(4). 2008)A

Description

  • Stems solitary, non-climbing, short and subterranean or visible above ground for about 5 cm, 3-3.5 cm diameter without sheaths, green. Leaves 9-12; leaf sheaths open, green with brown tomentum, with scattered, yellowish spines to 6 cm long, borne singly or in small groups; ocreas prominent, 4-10 cm long, densely brown bristly; knees absent; flagella absent; petioles 46-60 cm long, spiny as the sheaths; rachis 53-64 cm long, with few, straight spines abaxially; cirri absent; pinnae 21-25 per side of rachis, 22-30 cm long, 2-2.5 cm wide at the middle, lanceolate, borne in distant clusters of 2-6 pinnae, each pinna of a cluster spreading in a different plane, the apical pair joined for almost their entire length, minutely bristly on the margins, not bristly on the veins, yellowish at the bases. Staminate inflorescences to 1 m long, erect, branched to 3 orders, with at least 7 partial inflorescences; prophylls 14 cm long; partial inflorescence bracts tubular, not splitting laterally, with a prominent lobe at the apex; rachillae not known in their entirety; rachillae bracts 1.5 mm high, apiculate; floral bracteoles cupular, 2-lobed; old staminate flowers 3 mm long; calyx 1.5 mm long, split for half its length into 3 lobes; corolla 3 mm long, split to the base into 3 valvate petals; pistillate inflorescences 77 cm long, erect, not flagellate, branched to 2 orders, with 4-5 partial inflorescences; prophylls not known; partial inflorescence bracts tubular, splitting laterally as the fruits develop; rachillae 1-13, 1-3 cm long; rachillae bracts 1.5 mm high, apiculate; floral bracteoles cupular, 2-lobed; flowers 3.5 mm long (post-anthesis); calyx 2 mm long, split for about half its length into 3 lobes; corolla 2.5 mm long, split for most of its length into 3 valvate petals; fruits immature, yellowish. (Henderson, A.J., Ban, N.K. & Dung, N.Q., New species of Calamus (Palmae) from Vietnam in Palms (1999+) 52(4). 2008)A

Materials Examined

  • Vietnam. Phu Yen: Tuy Hoa District, route number 1 at Ca Pass near border with Khanh Hoa, 12°51'N, 109°23'E, ca. 100 m, 22 Jul 2007, A. Henderson and Ninh Khac Ban 3451 (Holotypus: HN! Isotypi: K! NY!).
    (Henderson, A.J., Ban, N.K. & Dung, N.Q., New species of Calamus (Palmae) from Vietnam in Palms (1999+) 52(4). 2008)A

Bibliography

    A. Henderson, A.J., Ban, N.K. & Dung, N.Q., New species of Calamus (Palmae) from Vietnam in Palms (1999+) 52(4). 2008