Artabotrys pleurocarpus Maingay ex Hook.f. & Thomson

Chen, Junhao & Eiadthong, Wichan, 2020, New species and new records of Artabotrys (Annonaceae) from peninsular Thailand, PhytoKeys 151, pp. 67-81 : 67

Artabotrys pleurocarpus Maingay ex Hook.f. & Thomson Fig. 5

Artabotrys pleurocarpus Maingay ex Hook.f. & Thomson, Fl. Brit. India 1: 54 (1872). Type: Peninsular Malaysia. Malacca, 6 Feb 1868, A.C. Maingay 3261 [Kew distribution no. 34] (lectotype K [K000381010], designated in Turner (2016) explicitly excluding material in packet; isolectotype BM [BM001014846]).

Distribution and habitat.

Peninsular Malaysia and peninsular Thailand (Fig. 6 ), in lowland rain forests.

Specimens examined.

Peninsular Thailand. Songkhla Province: Rattaphum District, Boripat Forest Park, 4 July 1986, J.F. Maxwell 86-444 (A) [A00571911]; idem, 6 April 2006, T. Insura 61 (BK, BKF). Satun Province: Thale Ban National Park, Ton Plio Falls, open area by stream, 115 m elev., 3 June 2001, R. Pooma et al. 2004 (BKF) [SN 134816]. Trang Province: Na Yong District, Ton Pliw Waterfall, 7 April 2006, T. Insura 62 (BK, BKF); idem, 7 April 2006, T. Insura 63 (BK, BKF); idem, 7 April 2006, T. Insura 64 (BK, BKF).

Notes.

This species was hitherto known from Malacca, Kedah and Perak in Peninsular Malaysia ( Sinclair 1955). Specimens of A. pleurocarpus from peninsular Thailand were formerly misidentified as A. kurzii Hook.f. & Thomson or identified to genus level; they were only recently re-identified during our preparation of the Artabotrys treatment for the Flora of Thailand. The specimens from peninsular Thailand and Peninsular Malaysia closely match one another in leaf and fruit morphology and there can be no doubt that they are conspecific. Therefore, this represents the first record of A. pleurocarpus in Thailand. Artabotrys pleurocarpus is distinct among the Thai species on account of its fruit morphology, with relatively few monocarps (up to 9 per fruit) that are prominently beaked (2-3 mm long), quite large (22-30 mm long, 15-20 mm wide) and borne on a long stipe (7-10 mm long). The fruits therefore superficially resemble those of Polyalthia species, but specimens can be easily assigned to Artabotrys if the inflorescence/infructescence hook is present. Although A. kurzii from Myanmar (Pegu) was previously confused with A. pleurocarpus , it bears little resemblance to A. pleurocarpus , differing in its obovate (vs. oblong-lanceolate to oblong-elliptic) leaves, mucronate (vs. caudate to acuminate) leaf apex and short petioles (1-2 mm long vs. 4-6 mm long).

Figures

Figure 5. Artabotrys pleurocarpus A habit and mature flower B habit and developing fruit C developing flowers on hooked inflorescence D fruits, showing monocarps borne on very distinct stipes. Photos: T. Insura.

Figure 6. Distributions of A. crassifolius, A. insurae, A. longipetalus and A. pleurocarpus in peninsular Thailand. Only the region in peninsular Thailand is shown; adjacent areas in Peninsular Malaysia and Myanmar are removed.