Strobilanthes hypomalla Benoist

Kladwong, Pornchai & Chantaranothai, Pranom, 2024, Notes on Strobilanthes (Acanthaceae) with capitate inflorescences in Thailand, PhytoKeys 244, pp. 89-126 : 89-126

14. Strobilanthes hypomalla Benoist , Bull. Mus. Natl. Hist. Nat. 27: 543. 1921.

Fig. 11 A

Type.

Vietnam, Dalat, 27 Nov 1911, Lecomte & Finet 1524 (lectotype P [ P 00218435 image!] designated by Kladwong and Chantaranothai 2022, pg. 182).

Distribution.

Thailand, Laos, Vietnam.

Ecology.

In dipterocarp forest, sandstone bedrock; 340–492 m alt., flowering and fruiting December.

Specimens examined.

Thailand, North-eastern: Bueng Kan, Phu Lang Ka NP, 492 m alt., 26 Nov 2017, Suddee & Puudjaa 5333 ( BKF); ibid., Phu Wua WS, 340 m alt., 15 Oct 2016, Suddee et al. 5561 ( BKF); ibid., trails to Tham Noi Waterfall, 1 Dec 2020, Kladwong et al. 539 ( KKU).

Preliminary conservation status assessment.

This species has an Extent of Occurrence ( EOO) of 10,177.798 km 2 and an Area of Occupancy ( AOO) of 16.000 km 2 and is assessed as the Endangered ( EN), B 1 a, b (i, ii, iii) following IUCN (2022). This species grows on sandy soil in dipterocarp forest and is only recorded from a few records. The changes of the habitat through increasing droughts and fire are likely to lead to the decline of S. hypomalla .

Notes.

Strobilanthes hypomalla resembles S. aprica , but differs in having greenish or yellowish green stems, linear-lanceolate leaf shape, and the outside of the corolla is pubescent. Moreover, the pollen of S. hypomalla is prolate or subprolate with a 3 - colporate aperture and longitudinal spinose ribs on the exine sculpturing as opposed to 3 - cryptoaperturate and with short conical spines over the exine in S. aprica ( Kladwong and Chantaranothai 2022) . According to the protologue of S. hypomalla , the corolla was described as glabrous outside but the specimens from Thailand show that it is pubescent. Further research based on more specimens is needed to comprehend this variation.

Figures

Figure 11. Distribution maps of Strobilanthes with capitate inflorescence in Thailand A S. graminea J. B. Imlay, S. hypomalla Benoist and S. kerrii Craib B S. paniculiformis J. R. I. Wood, S. paniculata (Nees) Miq. and S. phengklaii Kladwong & Chantar. C S. phyllocephala J. R. I. Wood & Scotland, S. phyllostachya Kurz and S. serpens (Nees) J. R. I. Wood & Scotland D S. speciosa Blume and S. squalens S. Moore.