 |
Figure 1. Argostemma ebracteolatum. A. habitat, leaves and inflorescences; B. inflorescences and flowers. KS 728 (photos by K. Souvannakhoummane).
A. pictum. C. habitat, leaves and inflorescences; D. inflorescences and flowers. Lanorsavanh 1075 (photos by S. Lanorsavanh).
Figure 2. Argostemma verticillatum. A. habitat, leaves and inflorescences; B. inflorescences and flowers. Lanorsavanh 1085 (photos by S. Lanorsavanh).
in Lanorsavanh & Chantaranothai, 2019.
|
ABSTRACT
Three species of Argostemma (Rubiaceae) are newly recorded for Lao PDR: A. ebracteolatum, A. pictum and A. verticillatum. Descriptions and photographs of the new records are provided, and a key to Argostemma in Lao PDR is presented.
KEYWORDS: Agrostemma, key, new record, Lao PDR, taxonomy
INTRODUCTION
Argostemma Wall., a genus of Rubiaceae of ca 100 species in the Old World tropics, is largely confined to the South-East Asia (Robbrecht, 1988) but with two species in tropical West Africa (Sridith & Puff, 2000; Mabberley, 2008). For Lao PDR, Newman et al. (2007a) and Newman et al. (2007b) first recorded a species of the genus, A. laeve Benn., from Khammouan province. Lanorsavanh & Chantaranothai (2013, 2016) recorded three species A. laotica Lanors. & Chantar., A. neurocalyx Miq. and A. siamense Puff from Bolikhamxai province, and, most recently, Tagane et al. (2017) recorded an additional species, A. lobbii Hook.f., from Bolikhamxai province.
During botanical surveys of the first author in northern Lao PDR, Luangphrabang Province in July 2014 with S. Souvanhnakhoummane, and Luangnamtha Province in August 2015 with C. Phongoudome and in the southern Attapeu Province in June 2014 with V. Lamxay, many unnamed specimens were collectedand identified and include new records for Lao PDR, viz Argostemma ebracteolatum E.T.Geddes, A. pictum Wall. and A. verticillatum Wall. In 1999, Sridith indicated the type specimens of A. ebracteolatum, A. pictum, A. pubescens, A. repens and A. rotundifolium were holotypes, but this is an error to be corrected to lectotypes, nevertheless the lectotypification was effectively done by him.
NEW RECORDS:
1. Argostemma ebracteolatum E.T.Geddes, Bull. Misc. Inform. Kew 1927(4): 165. 1927.
Type: Thailand, Chiang Mai, Mae Chaem (Me Cham), 14 Jul. 1922, Kerr 6276A (lectotype K! [K000760179], isolectotypes BK! [257307], BM! [BM000028695], designated by Sridith, 1999).
Ecology.— On limestone wet rock in mixed deciduous, deciduous and dry evergreen forests, 540–1,100 m alt.; flowering July and fruiting July to August.
Notes.— Argostemma ebracteolatum resembles A. thaithongae Sridith, endemic to Thailand, in the bell-shaped corolla and 5-merous flower, but differs in having not only being densely hairy on stem, leaves and inflorescence but also the exterior of the corolla. It is unlikely to be confused with other species in Laos as only A. neurocalyx has a bell-shaped corolla but is 4-merous.
2. Argostemma pictum Wall. in Roxb., Fl. Ind. (ed. Carey & Wall.) 2: 327. 1824.
Type: Malaysia, Penang, 1892, Wallich, Numer. List 8392 (lectotypeK! [K000172892]; isolectotypes K! [K000172894], K-W! [K-W001125373] designated by Sridith, 1999), non Korth., 1851.
Ecology.— On moist sandstone rocks with soil or on wet ground in evergreen forests, 100–410 m alt.; flowering June to July and fruiting June to August.
Notes.— Argostemma pictum resembles A. neurocalyx but it distinguished by the wheel-shaped corolla which is 5-merous, and very strongly recurved with the tip coiled.
3. Argostemma verticillatum Wall. in Roxb., Fl. Ind. (ed. Carey & Wall.), 2: 325. 1824;
Type: Nepal, Moreko, July 1821, Wallich, Numer. List 8394A(holotype K-W! [K-W001125376]). Fig. 2.
Ecology.— On moist rocks near small water-fall in evergreen forests, 740–2,200 m alt., flowering and fruiting July to August.
Notes.— Argostemma verticillatum is recognized by its curved filaments which its fused around the middle and forming a short filament tube. Because the Chinese species have free filaments (Chen & Taylor, 2011), therefore, we exclude China from the distribution information; further study is needed to clarify this character.
 |
| Figure 1. Argostemma ebracteolatum. A. habitat, leaves and inflorescences; B. inflorescences and flowers. KS 728 (photos by K. Souvannakhoummane). A. pictum. C. habitat, leaves and inflorescences; D. inflorescences and flowers. Lanorsavanh 1075 (photos by S. Lanorsavanh). |
 |
| Figure 2. Argostemma verticillatum. A. habitat, leaves and inflorescences; B. inflorescences and flowers. Lanorsavanh 1085 (photos by S. Lanorsavanh). |
Soulivanh Lanorsavanh and Pranom Chantaranothai. 2019. Notes on the Genus Argostemma (Rubiaceae) from Lao PDR. Thai Forest Bulletin (Botany). 47(1); 29-33. DOI: 10.20531/tfb.2019.47.1.06
