Schizostachyum aciculare Gamble (1896: 117–118

Sungkaew, Sarawood, Wong, Khoon Meng, Hodkinson, Trevor R., Thammanu, Siriluck, Cheysawat, Somboon & Teerawatananon, Atchara, 2024, Taxonomic revision of the bamboo genus Schizostachyum (Bambusoideae: Melocanninae) in Thailand, with two new species and five new records, lectotypifications and nomenclatural corrections, Phytotaxa 676 (3), pp. 263-286 : 266-267

(1) Schizostachyum aciculare Gamble (1896: 117–118 , pl. 104). Figs. 1A–E .

Type: — MALAYSIA, Malacca, Bukit Kepayang, November 1885, Alvins 2167 (holotype: SING [SING0194893!]).

Description: — Culms erect, 2–5(–15) m high, tips drooping, occasionally scrambling or clambering on other vegetations; internodes greyish green when young, yellowish green when mature, 25–55(–100) cm long, 0.5–2 cm in diameter, covered with white wax and grey hairs to glabrous; walls 0.8–1 mm thick; nodes with slightly raised nodal line, covered with short white to pale hairs around the node. Culm leaves: sheaths initially dark green, later greenish purple to yellowish green, 6–15(–22) cm long, apex symmetrical, truncate to slightly concave, base of outer margin without a projection, covered with appressed white hairs on abaxial side to glabrous; auricles inconspicuous to tiny lobed, 1–2 mm high, oral setae 5–10 mm long, more or less straight, or wavy toward the tips; ligules ca. 1 mm high, irregularly toothed, ciliate; blades deflexed, initially dark green to purplish green, later yellowish green to green, narrowly lanceolate, (2–)5–10(–16) cm long, hairy on adaxial side near the base. Foliage leaves: auricles inconspicuous to tiny lobed, up to 0.5 mm high, oral setae 5–10 mm long; ligules inconspicuous; blades (7)10–22(–29) × 1.3–6 cm, glabrous on both sides. Pseudospikelets green, narrowly fusiform, 3–4(–6) cm long; rachilla internodes (1–)1.4–1.7(–3) cm long; fertile florets 1, 2–3(–4) cm long, with terminal rachilla extension, 0.4–1 cm long, and sometimes with a tiny vestigial floret; lemmas tightly convolute, (1.7–) 2–2.8 cm long, short hairs all over; paleas tightly convolute, 2–3 cm long, not keeled, glabrous. Lodicules absent. Stamens: anthers yellow to green, 1–1.5 cm long; filaments loosely fused.

Distribution and ecology: — Thailand, Cambodia and Peninsular Malaysia. They usually grow along edges, in gaps or under the canopy of evergreen and semi-evergreen forests at 0–800 m alt.

Additional specimens examined: — THAILAND: North-eastern. Bueng Kan, Seka , 13August 2004, S. Sungkaew & A. Teerawatananon 187 (Thailand Natural History Museum) ; the same locality, 13 August 2004, S. Sungkaew & A. Teerawatananon 188 ( Thailand Natural History Museum) ; Bung Khla , 28 September 2009, C. Rattamanee M176 ( BKF197502 ) ; the same locality, 29 May 2022, S. Sungkaew et al. 1692 ( Thailand Natural History Museum) ; the same locality, 24 September 2022, S. Sungkaew & A. Teerawatananon 1711 ( Thailand Natural History Museum) ; Mukdahan, Kum Cha-ae, 11 February 1999, S. Laosakul et al. ST1 (K000682054). Eastern. Nakhon Ratchasima, Chok Chai , 30 December 1923, A.F.G. Kerr 8178 (K000631421, K000631422, K000631423, K000631425) ; Pak Chong , 21 August 1968, T. Smitinand 10446 (BKF52398, P02353551) ; the same locality, 31 October 1970, Charoenphol et al. 4388 ( BKF096211 , L1328884 ) ; the same locality, 9 June 2001, S. Sungkaew & A. Teerawatananon 090601-02 ( Thailand Natural History Museum) ; the same locality, 22 May 2002, J.F. Maxwell 02-125 ( BKF182361 ) ; the same locality, 18 October 2002, S. Sungkaew & A. Teerawatananon 181002-18 ( Thailand Natural History Museum) ; the same locality, 30 May 2022, S. Sungkaew & A. Teerawatananon 1696 ( Thailand Natural History Museum) ; Nakhon Nayok, Pak Phli , 25 September 2022, S. Sungkaew & A. Teerawatananon 1714 ( Thailand Natural History Museum) ; Sa Kaeo, Watthana Nakhon , 13 September 2008, C. Rattamanee M070 ( BKF197414 ) ; Chachoengsao, Tha Takiap , 27 August 2022, S. Sungkaew & al. 1702 ( Thailand Natural History Museum) ; the same locality, 27 August 2022, S. Sungkaew & al. 1703 ( Thailand Natural History Museum) ; the same locality, 27 August 2022, S. Sungkaew et al. 1704 ( Thailand Natural History Museum) ; the same locality, 23 October 2008, C. Rattamanee M096 ( BKF197411 ). South-eastern. Chanthaburi, Soidao , 28 May 2009, C. Rattamanee M127 ( BKF197504 ) ; the same locality, 17 January 1956, T. Smitinand 3175 ( BKF18828 ) ; Trat, Bo Rai , 19 December 1929, A.F.G. Kerr 17604 (K000631426, K000631427) ; Khao Saming District , 24 November 1924, A.F.G. Kerr 9422 (K000631543, K00631544, K000631545, K000631546) ; Klawng Yai , 11 April 1951, T. Smitinand 267 (P03143540) ; the same locality, 19 June 1952, T. Smitinand 1336 ( BKF6778 ) . CAMBODIA: South-western. Koh Kong, Thmar Bang , 19 August 2016, F.F. Merklinger 2016-18 (BKF210527, K003901760, K003901761, K003901762, SING0282014, SING0282015, SING0330207 ), the same locality, 24 November 2015, F.F. Merklinger 2015-69 (SING0282021, SING0282022 ) .

Conservation status: — Schizostachyum aciculare has an Extent of Occurrence (EOO) of 141,321.3 km 2, which places it in the Least Concern (LC) conservation category while its small Area of Occupancy (AOO) of less than 500 km 2 (56.0 km 2) places it in the conservation status of the Endangered (EN) category. However, there are many populations with a large number of individuals found in several protected areas and there is little pressure from any threats on this species. Based on IUCN (2023), S. aciculare is here placed in the Least Concern (LC) category.

Vernacular name: —ไผ่กะแสน (Phai Kasaen), ไผ่กะแสนขาว (Phai Kasaen Khao), ไผ่กะเสียน (Phai Kasian), ไผ่ วงเดือน (Phai Wongduean), ไผ่หลอด (Phai Lawt), ไม้ปล้องยาว (Mai Plongyao).

Notes: —Morphological variations are observed between populations of S. aciculare . The habitat type might affect the habit of S. aciculare since, from field observations, individuals growing in shaded areas in Khao Ang Rue Nai Wildlife Sanctuary and Khao Yai National Park as well as in Cambodia exhibited distally clambering culm habits, probably attributable to the slender culms entangling with a denser surrounding vegetation. In contrast, the individuals found in open areas as seen in Bueng Kan Province showed erect to suberect culms.

Nomenclatural notes: —According to the protologue, the type specimen of S. aciculare Gamble (1896: 117–118 , pl. 104) was collected by Mr. Alwis (No. 2167) at Rupayoong, Malacca in November 1885. However, Holttum (1958) mentioned the type specimen of Alvins (not Alwis sensu Gamble) that is kept in SING (S previously used) and gave the locality name using Bukit Kepayang instead of Rupayoong (which appears to be a mis-transliteration). Here, we have examined the type specimen and followed the collector and locality names provided by Holttum.

Figures

FIGURE 1. (A–E) Schizostachyum aciculare Gamble. (A) Young culm showing culm leaf sheath, node and parts of internodes; (B) Culm leaf sheath apex; (C) Young culm shoot; (D) Part of leafy branch; (E) Flowering branches. (F–J) S. kohchangense W.Arthan, Teerawat. & Sungkaew, sp. nov. (F & J) Young culms showing culm leaf sheaths; nodes and parts of internodes; (G) Young culm shoot; (H) Part of leafy branch; (I) Flowering branches. (K–M) S. cambodianum Merkl., Chhang & K.M.Wong. (K) Young culm showing culm leaf sheath, nodes and parts internodes (note basal projection from the outer margin of the culm sheath proper); (L) Flowering branch; (M) Close-up of culm node with primary branch bud. (N–P) S. nigrum W.Arthan, Teerawat. & Sungkaew, sp. nov. (N) Flowering branch; (O) Close-up of culm node with the characteristic ring of hairs; (P) Young culm showing culm leaf sheath (note basal projection of outer margin), node and parts internodes. (Photographed by A. Teerawatananon & D. Pathumthong).