Mnesithea mollicoma (Hance) A.Camus

Veldkamp, J. F., Heidweiller, J., Klaauw, M. A. F. van der, Koning, R. de, Kraaijeveld, A. R., Sosef, M. S. M. & Strucker, R. C. W., 2013, A revision of Mnesithea (Gramineae - Rottboelliinae) in Malesia and Thailand, Blumea 58 (3), pp. 277-292 : 285-286

8. Mnesithea mollicoma (Hance) A.Camus — Fig. 9

Mnesithea mollicoma (Hance) A. Camus (1919) 57. — Rottboellia mollicoma Hance (1871) 134. — Manisuris mollicoma (Hance) Kuntze (1891) 780. — [ Rottboellia corymbosa L.f. subvar. mollicoma (Hance) Roberty (1960) 65, comb. inval.]. — Coelorachis mollicoma (Hance) Bor (1962) 169. — Lectotype: Hance 7558 (holo G; K, fragm. L, W), designated by Roberty (1960: 66) (see note).

Mnesithea pubescens Ridl. (1905) 207. — Type: Ridley 11017 (holo K).

Rottboellia triflora F.T.Hubb. (1914) 257. — Mnesithea triflora (F.T.Hubb.) Jansen (1953) 309. — [ Manisuris triflora (F.T.Hubb.) Chase & Niles (1962) 230, comb. inval. (see note)]. — Type: Ledesma s.n. (holo BH; A, US, W).

? Rottboellia sp. 4 : Schmid (1958) 193.

Plants perennial. Culms 0.4–0.9 m long, pilose with scattered bulbous-based bristles. Cataphylls ovate to ovate-oblong, (4–)14–24(–32) by 2.5–5.5 mm, puberulous to pilose, apex acute to acuminate or mucronate. Nodes setose. Sheaths setose, margin pilose to ciliate. Ligule 1–3 mm long, margin setose. Contra-ligule absent. Blades flat, (9–)26–35(–47) cm by 6–12 mm, margins pectinate at base, hairy on both sides, setose behind the ligule, smooth. Peduncles solitary or paired, hairy. Spatheoles 8–16 cm long. Spikes 3.5–8 cm by 1.8–2.5 mm. Spikelets in the lower part with triads or all paired. Joints 3.6–5.2 mm long, glabrous to ciliolate at base, smooth. Sessile spikelets 4.4–6.2 mm long (incl. callus), longer than the joint. Callus hairy. Lower glume convex, ovate-oblong, hairy, coriaceous, cancellate, greenish yellow, sometimes with purplish margins, 6–7-nerved, lower part at keel smooth, apex winged; upper glume boat-shaped to concave, ovate-oblong, 3.3–5 mm long, 4–5-nerved, nerves anastomosing or not, ciliolate along the infolded margin, apex acute. Lemmas ovate-oblong, 2.8–4.1 mm long, glabrous to ciliolate along the margin, acute. First lemma epaleate or paleate, 2.5–3.8 mm long, 3–4-nerved; second lemma 3-nerved. Paleas 2-nerved, margin ciliolate; first palea ovate-lanceolate, 2.3–2.7 mm long; second palea ovate-lanceolate, 2.3–2.5 mm long. Anthers 1.6–2.1 mm long. Pedicel free from the joint, 4.2–6.4 mm long, glabrous, smooth. Pedicelled spikelets reduced to 2 glumes, laterally flattened, 0.6–0.9 mm long. Lower glume chartaceous, glabrous to margin ciliolate, apex winged. 2n = 18.

Distribution — Vietnam (widespread, fide Schmid 1958: 194), Thailand (N: Chiang Mai; E: Chaiyaphum; SE: Chan- thanaburi) to S China (Guangdong, Guangxi, Hainan); Malesia: Malay Peninsula (Johor),? Singapore (Wallich 8876, but never found there again), Sumatra (E Coast, fide Jansen 1953), Java (Priangan, Cianjur, see note), Palawan.

Habitat — Partly shaded, disturbed and overgrown places, sunny, dry places, in hedges and thickets, light deciduous (oakdipterocarp) forest, along roads, granite bedrock, 400–1200 m altitude (‘low altitudes’ in Palawan) .

Ecology — Beumée (1927: 419) reported the presence of myrmecochory (sub M. pubescens ).

Uses — Backer (1950: 176, sub M. pubescens ) noted that a large amount of soft leaf was produced which was well-liked by cattle.Analyses showed a very satisfactory nutrition value. The yield was much lower than that of Panicum maximum Jacq. , however, and did not increase after manuring.

Notes — The type of Rottboellia mollicoma is represented in K by two sheets. One has no original label, but is annotated ‘1862’ and bears a note by C.B. Clarke “ This is the type ”. Hance said he had collected the species first in October 1861. The other sheet has an original label which bears the date August 1869. Roberty with an exclamation mark following Clarke ’ s selection designated the G duplicate as the lectotype (‘type’). However, if a specimen with the date October 1861 does exist that should take precedence as the lectotype.

Mnesithea mollicoma differs mainly from M. cancellata by the pubescence of the spikelet and the shorter pedicelled spikelets. Msesithea mollicoma is usually densely hairy, but some exceptions were observed:

Backer s.n. (1918) from Java has the lower glumes of the sessile spikelets almost glabrous to nearly so with hardly excurrent nerves. This is the only specimen seen from Java. Beumée (1927) and Backer (1950) have suggested that it was imported, e.g. with rubber seeds from Malaya; in 1918 it had locally become quite common in Imperata-fields. More recent collections are lacking.

Ledesma s.n., the type of Rottboellia triflora , has nearly glabrous culms and blades, but the nodes are hairy. The upper glume is flatter than usually seen, slightly keeled with ciliolate margins. The dimensions of the width of the blade, the length of the glumes, lemmas, paleas are all rather small. This form seems to be linked to the more ‘normal’ representatives of M. mollicoma by Smitinand 1827 from Thailand which has nearly glabrous culms, nodes and blades. Moreover, the leaves of this collection are exceptionally narrow (4–7 mm) and the plant is only 40 cm tall. Because of this transitional form, al- beit with quite a different provenance, Rottboellia triflora has been included in this species. More material from Palawan is required to see how variable that population is and whether or not it should have a separate status after all.

Chase & Niles (1962) is an off-set of a card system prepared at the Smithsonian Institution, Washington (D.C.). Although there is no disclaimer in the introduction, one should regard any new combination or lectotypification made there as not having been validly published (Art. 34.1.a), being personal notes and not officially published in subsequent publications. See also Ramella et al. (2011).

Differs from the Malesian / Thai congeners in: Sheaths setose. Sessile spikelet callus puberulous; lower glume cancellate, hairy.

Most similar is M. glandulosa :

1. Sheaths glabrous to hairy.Peduncles glabrous. Sessile spikelet callus ciliolate; lower glume smooth, laterally with small appendages......................... M. glandulosa

1. Sheaths setose. Peduncles hairy. Sessile spikelet callus puberulous; lower glume cancellate........ M. mollicoma

Figures

Fig. 9 Mnesithea mollicoma (Hance) A.Camus. a. Joint and pedicel; b. sessile spikelet (all: Shimizu et al. T. 10473, L).