Calamus cheirophyllus J.Dransf. & W.J.Baker, 2014

Baker, William J. & Dransfield, John, 2014, New rattans from New Guinea (Calamus, Arecaceae), Phytotaxa 163 (4), pp. 181-215 : 189-191

4. Calamus cheirophyllus J.Dransf. & W.J.Baker , sp. nov. Type:— PAPUA NEW GUINEA. Eastern Highlands Province: Kundiawa Subdistrict, Karimui , foothills of Mt. Karimui , 1280 m, 6°28’S, 144°40’E, 30 November 1972, Zieck NGF 36515 (holotype K!, isotypes BH, L!, LAE!) .

Diagnosis:— Distinguished by the slender stems, ecirrate leaves with conspicuous petiole and 7–9 leaflets crowded at the petiole tip, the leaf hence appearing almost palmate, the short, erect, eflagellate inflorescence, with few rather inflated rachis bracts and short but not condensed rachillae; resembling some forms of C. lauterbachii , but differing in the smaller size, the narrow leaflets with less conspicuous cross veins, the less robust, unarmed ocrea and the lax rachillae.

Slender rattan climbing to 4.5 m only, densely clustering (up to 50 stems per clump). Stem with sheaths 6.5–13 mm diam., without sheaths to 6 mm diam.; internodes to 11cm. Leaf ecirrate, 30–50 cm long; sheath drying pale green, with abundant mid-brown indumentum, sheath spines abundant, slender, persistent, very varied in length, 1–12 × 0.5–2 mm, scattered or sometimes in horizontal groups, straw-coloured, horizontal or slightly reflexed, narrow triangular, laminar, spines around the leaf sheath mouth crowded, very slender, sometimes much larger than on the rest of the sheath and erect, to 15 mm; knee present but scarcely conspicuous, to 18 × 5 mm, drying same colour as sheath, armed as the rest of the sheath; ocrea well developed, conspicuous, 7–13 × 0.5–1 cm, papery, splitting into 2 lobes and disintegrating into a fibrous network, bearing abundant brown scales, unarmed, but sheath spines often penetrating through network; flagellum present, to 1.8 m long; petiole 9–12 cm long, 2–4 mm wide, densely armed with short straw-coloured spines on all surfaces and bearing abundant brown indumentum; rachis very short, 2–3 cm long, armed abaxially with a few recurved spines, adaxially unarmed, both surfaces densely covered with brown indumentum; leaflets 7–9 in total, arranged in a fan at the tip of the petiole, narrowly elliptic, 24–35 × 1–3 cm, unarmed apart from black bristles to 1 mm long along margins and adaxial surface of mid-vein, leaflets lacking indumentum, transverse veinlets close, sinuous, moderately conspicuous. Staminate inflorescence not seen. Staminate flowers not seen. Pistillate inflorescence 14–34 cm long, including peduncle 7–23 cm, branched to 2 orders; prophyll borne 5–7 cm above the base, to 7 × 0.5 cm, tubular and loosely sheathing, papery, with a truncate tip, becoming lacerate, bearing abundant brown indumentum and rarely with a few scattered straw-coloured spines, to ca. 1 mm; peduncular bracts absent; rachis bracts similar to prophyll but shorter and more inflated; primary branches 4, crowded together, 2–6 cm long, with up to 12 rachillae; rachillae crowded, ± straight, the basal the longest, to 20 × 1 mm, decreasing towards the tip of the first order branch; rachilla bracts triangular, acuminate, membranous, striate, 1.5 × 1 mm, distichous, unarmed, partially obscured by caducous pale brown indument; proximal floral bracteoles cup-shaped, ca. 1.5 mm diam., distal floral bracteoles cup-shaped, 1 × 1 mm, scar from sterile staminate ca. 0.3 mm diam. Sterile staminate flower only known as very young buds ca. 1.5 mm diam. Pistillate flower buds with calyx ca. 2 mm long, with low triangular lobes; petals ca. 2 × 1mm; other parts very immature. Fruit globose, 10 × 10 mm, with a beak to 1 × 1 mm and covered with 18 vertical rows of matt pale straw-coloured scales with pale margins. Seed globose, 7.5 × 7.5 × 6.5 mm, with a longitudinal groove on one side, seed surface very shallowly grooved and dimpled, endosperm homogeneous, embryo basal. ( Fig. 4 )

Distribution:— Known from montane forest at Karimui, Kundiawa Subdistrict, Eastern Highlands Province and a possible record from Erave in Southern Highlands Province in Papua New Guinea.

Habitat:— Montane forest at approximately 1100–1400 m above sea level.

Uses:— None recorded.

Vernacular names:— Tiwi (Koijari).

Specimens examined:— PAPUA NEW GUINEA. Eastern Highlands Province: Kundiawa Subdistrict, Karimui, foothills of Mt. Karimui , 1280 m, 6°28’S, 144°40’E, 30 November 1972, Zieck NGF 36515 (holotype K!, isotypes BH, L!, LAE!) ; Kundiawa Subdistrict, Karimui, lower slopes of Mt. Karimui , 1340 m, 6°28’S, 144°40’E, 30 November 1972, Zieck NGF 36516 (BH, K!, L) ; Kundiawa Subdistrict, Karimui , 1340 m, 6°28’S, 144°40’E, 30 November 1972, Zieck NGF 36517 (BH!), Zieck NGF 36518 ( LAE!) . Southern Highlands: Erave Subdistrict, Erave , 1067 m, 6°35’S, 143°55’E, 27 July 1971, Zieck NGF 36257 (A, BH, BRI, CANB, K!, L, LAE!) .

Notes:— This slender mountain rattan ( Fig. 4 ) is most immediately recognised by the superficially palmate appearance of its leaves, in which the 7–9 pinnately arranged leaflets are crowded at the apex of a relatively long petiole. Though it bears a well-formed flagellum, the inflorescences are eflagellate and erect, measuring up to only 34 cm in length in material seen by us. The primary bracts of the inflorescence are slightly inflated and papery, tending to tatter and disintegrate. A conspicuous, unarmed, inflated ocrea to 13 cm in length that encircles the stem is also present, though, like the primary bracts, it is papery and tends to disintegrate. The species resembles C. lauterbachii Beccari (1908: 491 ; synon. C. humboldtianus Becc. in Gibbs [1917: 93]), but differs in its smaller stature, the narrow leaflets, with less conspicuous cross veins, the less robust, unarmed ocrea, and the laxly arranged (rather than densely congested) rachillae.

One collection (Zieck 36257) probably belongs to this species. It is even more slender than the other cited collections, and is said to grow into the forest canopy. It has very few spines on the sheaths and there are generally fewer leaflets. The specific epithet (Greek – hand leaf) refers to the unusual, almost palmate appearance of the leaf.

Figures

FIGURE 4. Calamus cheirophyllus. A. Habit, including leaf sheath, ocrea, leaf and inflorescence. B. Leaf sheath, ocrea and inflorescence. C. Portion of pistillate rachilla. D. Infructescence attached to leaf sheath, showing tattering ocrea. E. Fruit. F, G. Seed in two views. I. Seed in longitudinal section. Scale bar: A = 6 cm; B = 2.5 cm; C = 2.5 mm; D = 3 cm; E = 1 cm; F–I = 7 mm. All from Zieck NGF 36515. Drawn by Lucy T. Smith.