Calamus dioicus Lour., Fl. Cochinch. : 211 (1790)

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Distribution

Indochinese endemic. Vietnam (Central Annam and Cochinchina). (Evans, T., Sengdala, K., Thammavong, B., Viengkham, O.V. & Dransfield, J. 2002: A Synopsis of the Rattans (Arecaceae: Calamoideae) of Laos and Neighbouring Parts of Indochina)A

Discussion

  • The species treated as C. dioicus by Beccari (1908) is certainly a distinct one with no other available name. In the absence of any type material this seems the most reasonable and practical interpretation to put on Loureiro's poor description. Since Beccari (1908) has long been the standard reference for the genus, and he presents a perfectly clear account including a photograph and named specimen, this forms the defacto type description and implicit neotype for field workers in the region. Loureiro did not indicate a type and no candidate has been found amongst his remaining specimens. Merrill (1935) presented several very weak arguments for upsetting this stability. Four criticisms of his account are: (1) he offers no morphological discrepancy between the species of Loureiro and Beccari; (2) local names are notoriously inconsistent and so unreliable guides to taxonomic identity in this context; (3) one of the two specimens he mentions, ClemensJ. & M. S. 3100, is in fact Calamus tetradactylus Hance (we have not seen the other); and (4) C. viminalis is recorded commonly in Indochina but never in the Moluccas, although he states the reverse. Unless previously overlooked specimens collected by Loureiro become available we would argue strongly against changing the present, perfectly workable situation. The male specimen cited by Conrard (Poilane 5042 from Nhatrang, now in P) cannot confidently be placed in C. dioicus because, although the leaves match reasonably well, the partial inflorescences are enormously long and more closely resemble C. solitarius. It is perhaps a mixed collection. We consider Newman, M. 158 to be a satisfactory match for the neotype and the first male plant known; we recommend that the description of the male inflorescence given by Gagnepain & Conrard (1937) and based on Poilane 5042 should be disregarded. See Key for differences from C. kingianus. Beccari's description of the type cannot be faulted but the following comments on Newman, M. 158 are added: Sheath and leaves are notable for drying much darker than C. tetradactylus and other close allies. Sheathed stem to 8 mm diameter, unsheathed stem to 4 mm. Knee indistinct, ocrea not tubular, thickly hispid, < 1 cm long. Leaves (excluding leaflets) up to 0.45 m. Petiole 10 cm, lightly armed adaxially and abaxially. Traces of dark scurf remain on the rachis. Leaflets are grouped from base to tip 4- 2 - 3 on one leaf and 4 - 4 on the other, the terminal two are joined at the base for less than 10% of their length and the basal two are not at all reflexed. Leaflets up to 35 x 2.5 cm, with a notably long, slender, bristly tip. Adaxially three costae prominent, all three bearing many short, appressed bristles, abaxially three costae prominent, all naked, margins with many delicate spinules. Male inflorescences (two preserved in K) both very slender, flagelliform, about 0.8 m long, branched to two orders only, bearing one and three partial inflorescences respectively. Primary bracts unremarkable: tightly sheathed, lightly clawed, ending in a short, pointed limb, falling short of or just reaching the base of the primary branch. Partial inflorescences to 9 cm long excluding terminal rachilla, bearing 5 - 8 rachillae which decline in length distally to give a pyramidal outline. Secondary bracts tightly sheathing, unarmed. Rachillae slender, arising just outside mouths of rachilla bracts, emerging at right angles to the branch and often slightly recurved, up to 5 cm long and bearing up to 13 flowers on each side. Rachilla bracts very short, funnel-shaped with a broad mouth and back-curled pointed limb. Involucres placed fully outside the rachilla bracts, cups about 1 mm deep, set so that the flowers sit exactly perpendicular to the axis, giving the rachillae a very neat, regular appearance. Flowers apparently close to anthesis, about 4 mm long, the calyx slightly less than half the corolla length, with three shallow, acute limbs. Magalon (1930) reports this species from several localities in north Vietnam but since his description specifies a cirrate species and his voucher specimen, Magalon 27 from Annam, is clearly in Calamus Section Phyllanthectus (probably C. palustris) this report can be disregarded. (Evans, T., Sengdala, K., Thammavong, B., Viengkham, O.V. & Dransfield, J. 2002: A Synopsis of the Rattans (Arecaceae: Calamoideae) of Laos and Neighbouring Parts of Indochina)A

Biology And Ecology

  • Evergreen forest at 200 m. (Evans, T., Sengdala, K., Thammavong, B., Viengkham, O.V. & Dransfield, J. 2002: A Synopsis of the Rattans (Arecaceae: Calamoideae) of Laos and Neighbouring Parts of Indochina)A

Conservation

  • Unknown, further research required. (Evans, T., Sengdala, K., Thammavong, B., Viengkham, O.V. & Dransfield, J. 2002: A Synopsis of the Rattans (Arecaceae: Calamoideae) of Laos and Neighbouring Parts of Indochina)A

Common Name

  • rani (Vietnam, Moi), may sap, may tre (Vietnam, Annamese). (Evans, T., Sengdala, K., Thammavong, B., Viengkham, O.V. & Dransfield, J. 2002: A Synopsis of the Rattans (Arecaceae: Calamoideae) of Laos and Neighbouring Parts of Indochina)A

Uses

  • None recorded. (Evans, T., Sengdala, K., Thammavong, B., Viengkham, O.V. & Dransfield, J. 2002: A Synopsis of the Rattans (Arecaceae: Calamoideae) of Laos and Neighbouring Parts of Indochina)A

Materials Examined

  • VIETNAM (CENTRAL. ANNAM): Thua Thien Province, Bach Ma National Park, 19 Jan. 1990, (stam.), Newman, M. 158 (K). (COCHINCHINA): Chiao-Xhan Mts, March 1879, (fr.), Pierre 4834 (P, FI-B). (Evans, T., Sengdala, K., Thammavong, B., Viengkham, O.V. & Dransfield, J. 2002: A Synopsis of the Rattans (Arecaceae: Calamoideae) of Laos and Neighbouring Parts of Indochina)A

Bibliography

    A. Evans, T., Sengdala, K., Thammavong, B., Viengkham, O.V. & Dransfield, J. 2002: A Synopsis of the Rattans (Arecaceae: Calamoideae) of Laos and Neighbouring Parts of Indochina