Arundinella filiformis Janowski

Veldkamp, J. F., 2015, Arundinella (Gramineae) in Malesia with notes on other taxa and on aluminium accumulation, Blumea 59 (3), pp. 167-179 : 171

1. Arundinella filiformis Janowski

Arundinella filiformis Janowski (in Janowski & Mez 1921) 85; (1922) 26. — Type: Loher 7228 (holo M; K, US).

[ Arundinella miliacea (Link) Nees ‘forma minor ’ Nees (1850) 102,see note. — Voucher: Cuming 667 (CGE, K, L, US, W)].

Arundinella hispida (Humb. & Bonpl. ex Willd.) Kuntze forma humilior Hack. (1904) 527. — Arundinella hispida (Humb. & Bonpl. ex Willd.) Kuntze subsp. humilior Hack.(1906) 179;(1907a) no.606. — Arundinella humilior Jansen (1953) 232 (see 233 for correction of error in basionym). — Type: Faurie 756 (holo W; iso possibly in A, B, BM, BR, F, GH, H, TI, W. Not found in K). See note.

Arundinella caespitosa Janowski (in Janowski & Mez 1921) 85;(1922) 26. — Lectotype: BS 30 (Foxworthy) (holo W, fragm.in L; BO, K),designated here.

[ Arundinella montalbanica Elmer (1939) 3807,nom.nud.in syn. — Voucher: Elmer 17433 (PNH†; K, L, U)].

Arundinella agrostoides auct. non Trin.

Arundinella ciliata auct. non Miq.

Arundinella hispida auct. non Kuntze.

Arundinella miliacea auct. non Nees.

Arundinella nepalensis auct. non Trin.

Arundinella pubescens auct. non Hack. & Merr.

Plants perennial. Culms tufted, 0.14–0.7 m long. Nodes glabrous to puberulous. Sheaths glabrous to margins hairy to sparsely pilose with bb hairs. Throat glabrous to hairy. Ligule 0.3–0.7 mm high. Blades rather stiff or rigid, flat or involute, linear, 3.5–16 cm by 0.5–1(–3) mm (when flattened out), glabrous, exceptionally pilose on both sides, margins smooth or scaberulous or sparsely pilose. Peduncle glabrous under the panicle. Panicle loosely contracted, exceptionally lax, not interrupted at base, 5–16 by 1–2(–4) cm, lowermost branch solitary, rarely paired, longest branch 1.5–10 cm long, angular, smooth to scaberulous or puberulous, not pilose, rarely sparsely pilose. Pedicels smooth to scaberulous to puberulous. Spikelets 3.2–5 mm long, greenish or yellowish or brownish or purple suffused. Glumes glabrous; lower glume 2.3–3.8 mm long, 0.55–0.84(–1) times as long as the spikelet, distinctly shorter to slightly longer than the lower lemma, apex acute to mucronate, 3- or 5-nerved; upper glume 5-nerved, apex long-acuminate. Lower lemma neuter (paleate) or male, 2.6–3.8 mm long, 3- or 5-nerved, apex acute to acuminate; upper lemma 1–2.5 mm long, castaneous in fruit, microscopically scaberulous (40 ×!), 0-nerved, callus hairs 0.3–0.6 mm long, 0.19–0.43 times as long as the lemma, apex acute, without lateral setae, awn distinctly exserted beyond the glumes, geniculate, 3.5–9.5 mm long when dry, column 0.4–2.5 mm long when dry. Anthers 3, 0.8–1.5 mm long.

Distribution — Taiwan (no locality: Faurie 756, W), Malesia: Lesser Sunda Isl. (Flores, Sumba), Philippines (Luzon, Palawan, Panay, Samar), New Guinea (Irian Jaya: Idenburg R.).

Habitat — On (lime)stone near or in running water, sometimes partly submerged, along forest edge, 125–780 m altitude. Few collections are provided with details; when there is, it is often said to have been found near or even submerged in water. Kneucker Gram. Exsicc. 606 (Merrill) (K, L, etc.) has an extensive label, where it is stated to have been found immediately above the level of high tides in the shade of Syzygium mimicum (Merr.) Merr. ( Myrtaceae ), a facultative rheophyte, the rheophytic Atalantia linearis (Blanco) Merr. ( Rutaceae ), and Homonoia riparia Lour. ( Euphorbiaceae ), while other her- baceous plants were absent in the neighbourhood. The dense root system also suggests that this species is a rheophyte.

Notes — The holotype ( Faurie 756) of Arundinella hispida f. humilior is also a syntype of A. caespitosa . It is the only collection from Taiwan that has come to my attention. Perhaps Ohwi 1424 ( US) not seen by me, but mentioned by Phipps (1967a: 1047) belongs here or to A. taiwanica .

Arundinella caespitosa , A. filiformis , and A. hispida subsp. humilior have often been regarded as synonymous with A. miliacea . However, the latter combination was mentioned only by Nees (1840) and doubtfully validly made by Nees (1850) as he merely cited ‘ Acratherum ’ which has been regarded as an indirect reference to Acratherum miliaceum Link. Even when accepted, the combination is not applicable to Malesian material, as it is a synonym of A. nepalensis which does not occur in that region. The so-called ‘forma minor Nees’ is not a name, but a diagnose. Sun & Phillips (2006: 569) reduced this to A. pubescens Merr. & Hack.

The Sumba collection by Monod de Froideville (1775, K, L) is an exceptionally large specimen, both in the vegetative and the generative parts. The measurements in brackets given above refer to this one. It is distinctly perennial with sterile shoots and cataphylls. There are no ripe spikelets, so it can not be seen whether the upper florets will turn castaneous, as in the others. Without additional material this collection is best maintained as a giant A. filiformis . The K specimen was sampled by Teerawatananon for molecular research (Jodrell Lab. no. 22521).