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

Baker, William J. & Dransfield, John, 2014, New rattans from New Guinea (Calamus, Arecaceae), Phytotaxa 163 (4), pp. 181-215 : 207-209

12. Calamus spanostachys W.J.Baker & J.Dransf. , sp. nov. Type:— INDONESIA. Papua Province: Nassau Mountains [Sudirman Mountains], 700 m, October 1926, Docters van Leeuwen 10473 (holotype L!, isotypes BO, K!)

Diagnosis:— Distinguished by its extremely slender, short stems, which apparently lack flagella, the ecirrate leaves with only two or three pairs of leaflets, the apical pair being substantially larger than the lower one, and by the short, erect inflorescence branched to only one (pistillate) or two (staminate) orders.

Very slender rattan to 1.5 m. Stem with sheaths 3–5 mm diam., without sheaths 2–3 mm diam.; internodes 7–11 cm. Leaf ecirrate, to 37 m long including petiole; sheath mid-green, with scattered, caducous indumentum on young sheaths, sparsely armed in distal portion of sheath, spines to 12 mm long, 0.5 mm long at the base, narrowly triangular; knee scarcely developed, unarmed or sparsely spiny; ocrea scarcely developed; flagellum absent in available material; petiole 7–13 mm long, 2–3 mm wide at base; rachis 7–18 cm, unarmed or sparsely armed with short, reflexed spines; leaflets 2–3 on each side of rachis, subregular, lanceolate, basal and mid-leaf leaflets 12–19 × 1–2.2 cm, apical leaflets 22–29 × 2.5–4 cm, apical leaflet pair united up to one quarter of their length, leaflets sparsely armed with minute spines on margins and abaxial surface, lacking indumentum, transverse veinlets conspicuous. Staminate inflorescence erect, ca. 36 cm long including 8 cm peduncle and 5 cm flagelliform tip, branched to 2 orders; prophyll 8 × 0.3 cm, closely sheathing, opening eccentrically at the apex, with sparse indumentum, sparsely armed as rachis; peduncular bracts absent, rachis bracts similar to prophyll, to 6 × 0.3 cm; primary branches 4, to ca. 6 cm long, ca. 8 cm apart, with up to 10 rachillae; rachillae 8–21 mm × ca. 1 mm mm, straight to slightly recurved; rachilla bracts minute, triangular, distichous; floral bracteole 1.5 × 1 mm, deeply cupshaped. Staminate flowers ca. 2.5 × 1.4 mm in bud; calyx 1.3–1.4 mm diam., tubular in basal 0.7–1 mm, with 3 lobes 0.5-0.6 × 1 mm; corolla ca. 1 × 1 mm in bud, tubular in basal ca. 0.6 mm; stamens 6, filaments 1–1.2 × 0.1 mm, anthers 0.7-1 × 0.2 mm; pistillode absent. Pistillate inflorescence similar to staminate inflorescence, to 16 cm long including 3–4 cm peduncle and 1–6 cm flagelliform tip, branched to 1 order; prophyll 3 × 4 cm, closely sheathing, minutely armed; peduncular bracts absent, rachis bracts similar to prophyll; primary branches (= rachillae) 2–4; rachillae 3.3–4 mm × ca. 2 mm, erect, relatively robust; rachilla bracts 2 × 2 mm, distichous; floral bracteoles cup-shaped, scar from sterile staminate conspicuous. Pistillate flowers ca. 2.5 × 1.7 mm in bud; calyx ca. 1.7 mm diam., tubular in basal ca. 1.9 mm, with 3 lobes to ca. 0.6 × 0.7 mm; corolla ca. 2.2 × 1.3 mm, tubular in basal ca. 1.6 mm, with 3 lobes to 0.6 × 0.7 mm; staminodes forming membranous cup around gynoecium, ca. 1 mm high, bearing 6 vestigial anthers; ovary immature, 1.2 × 0.6 mm, globose, style scarcely developed. Sterile staminate flowers ca. 1.5 × 0.8 mm in bud, similar to staminate flower, but with empty anthers. Fruit immature, globose, 11 × 8 mm including beak to ca. 1 mm long, with 15 longitudinal rows of scales, pale brown when dried. Seed not seen. ( Fig. 12 )

Distribution:— Known from a single gathering near the Upper Rouffaer River in the Sudirman Mountains.

Habitat:— Primary forest around 700 m.

Uses:— None recorded.

Vernacular Names:— None recorded.

Specimens examined:— INDONESIA. Papua Province: Nassau Mountains [Sudirman Mountains], 700 m, October 1926, Docters van Leeuwen 10473 (holotype L!, isotypes BO, K!) .

Notes:— This rattan ( Fig. 12 ) has been collected only once during the 1926 Dutch-American expedition to New Guinea, which explored the upper reaches of the Rouffaer River from the Mamberamo basin. It is an extremely slender, short-stemmed species, lacking flagella (or indeed cirri) in the material seen by us, with only two or three pairs of leaflets, the apical pair being substantially larger than the lower ones. Its inflorescences are erect and short, with a poorly developed flagelliform tip, and are branched to only one (pistillate) or two (staminate) orders (hence the species epithet). Of the New Guinea rattans, Calamus spanostachys is most similar to C. kebariensis Maturbongs et al. (2014: 235) from the Bird’s Head Peninsula, which differs in being largely unarmed and bearing leaves with numerous, fine, regularly arranged leaflets.

Figures

FIGURE 12. Calamus spanostachys. A. Habit, including leaf sheath, leaf and pistillate inflorescences. B. Leaf sheath with staminate inflorescence. C. Staminate rachilla. D. Pistillate rachilla with young fruit. E, F. Staminate flower bud whole and in longitudinal section. G. Fruit. Scale bar: A = 4 cm; B = 3 cm; C = 2.5 mm; D = 4 mm; E, F = 1.1 mm; G = 7 mm. All from van Leeuwen 10473. Drawn by Lucy T. Smith.