Calamus seriatus A.J.Hend. & N.Q.Dung, 2010

Henderson, Andrew & Dung, Nguyen Quoc, 2010, Notes on rattans (Arecaceae) from Vietnam, Phytotaxa 8, pp. 25-33 : 31

Calamus seriatus A.J.Hend. & N.Q.Dung , sp. nov. ( Plate 3 )

A speciebus similibus ( Calamus flagellum , C. guruba , C. rhabdocladus , C. rudentum ) pinnis 8–9 aggretatis in duo catervas distantes differt.

Type:— VIETNAM. Khanh Hoa Province: Khanh Vinh District, Khanh Trung Commune , Suoi Ca Village , 300–400 m, 21 May 2007, N.Q. Dung 2004 (holotype: FIPI!, isotype: NY!) .

Stems clustered, climbing, to 10 m long, 1.8 cm diam. with sheaths. Leaf sheaths closed, green with brown tomentum, densely covered with yellowish spines to 1.5 cm long, those at the sheath apices longer, to 4 cm long, forming rows on either side of sheath apices and petiole bases; ocreas scarcely developed; knees absent; flagella present, to 60 cm long; petioles to 30 cm long, spiny laterally and abaxially as the sheaths; rachis to 42 cm long, with scattered, solitary, recurved spines abaxially; cirri absent; pinnae 8–9 per side of rachis, 29–35 cm long, 2–3 cm wide at the middle, linear–lanceolate, arranged in two distant groups of 5 pinnae distally and 3–4 proximally, scarcely bristly along the margins, the apical pair of pinnae joined distally for one third to one half their length. Staminate inflorescences to 0.7 m long, arching, flagellate, branched to 2 orders, with 4 partial inflorescences; prophylls not seen; partial inflorescence bracts tubular, briefly splitting at the apices, without spines; rachillae 5–6 per partial inflorescence, 2–5 cm long; staminate flowers not seen; pistillate inflorescences not seen; fruits not seen.

Distribution and habitat: —Endemic to southern Vietnam in Khanh Hoa Province in primary, evergreen forest at 300–400 m elevation.

Local names and uses: — may cam. The stems are used in basketry.

Discussion: — Calamus seriatus (named for its rows of spines at sheath apices) appears most similar to that group of species having the leaf sheath spines conspicuously longer at the sheath apices ( C. flagellum Griffith ex Martius (1853: 333) , C. guruba Buchanan-Hamilton in Martius (1838: 211), C. rhabdocladus Burret (1930: 884) and C. rudentum Loureiro (1790: 209)) . It differs from all these in its 8–9 pinnae per side of the rachis arranged in two distant groups with the apical pair joined at their bases, versus 27–65 pinnae per side of the rachis arranged regularly or sometimes irregularly with the apical pair not joined at their bases.

Figures

PLATE 3. Left. Calamus parvulus—leaves and flagella. Right. Calamus seriatus—leaf sheath spines, longer at sheath apices.