Strobilanthes chiangdaoensis Terao

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

5. Strobilanthes chiangdaoensis Terao , Acta Phytotax. Geobot. 32 (1–4): 31. 1981.

Figs 2 , 10 B

Type.

Thailand, Chiang Mai, Doi Chiang Dao, 4 Dec 1965, Hennipman 3187 (holotype L [ L 0002847!]; isotypes C [ C 10005196 image!], BKF!, K [ K 001514861!], KYO!).

Distribution.

Endemic to Thailand.

Ecology.

On rugged limestone ridge, open areas in mixed evergreen and deciduous forests; 800–2,190 m alt., m alt., flowering and fruiting from September to March.

Selected specimens examined.

Thailand, Northern: Mae Hong Son, Pang Mapha, Tham Lot, 925 m alt., 11 Nov 2004, Maxwell 04-698 ( BKF, CMUB, L 2 sheets); Chiang Mai, Doi Chiang Dao, 1050 m alt., 4 Dec 1965, Hennipman 3187 ( C, BKF, K, KYO, L); ibid., 500–1600 m alt., 3 Jan 1966, Tagawa et al. 4039 ( AAU, BKF, K, KYO- 3 sheets, P); ibid., 1,510 –2,190 m alt. 8 Feb 1983, Koyama et al. 33225 ( BKF, KYO); Chiang Rai, Mae Fa Luang, Doi Tung, 1,300 m alt., 22 Oct 1995, Pooma 1176 ( BKF, CMUB); ibid., 1,400 m alt., 5 Nov 2004, Maxwell 04-573 ( L); ibid., Huai Khrai, near Wat Phra That Doi Tung, 1,359 m alt., 15 Sept 2012, Chamchumroon et al. VC 5434 ( BKF- 2 sheets, E); Phayao, Chiang Kham, Doi Pha Dam, Ban Pang Tham, 1,030 m alt., 14 Nov 2012, La-ongsri et al. 25886 ( QBG); Wang Nuea, Ban Paak Bok, 1,100 m alt., 19 Jan 2006, Suksathan 3659 ( QBG); Lampang, Ngao, Ban Pha Daeng, 800 m alt., 16 Jan 2006, Suksathan 3614 ( KYO, QBG).

Preliminary conservation status assessment.

This species has an Extent of Occurrence ( EOO) of 19,556.802 km 2 and an Area of Occupancy ( AOO) of 32.000 km 2 and is assessed as Vulnerable ( VU), B 1 a, b (i, ii, iii) following IUCN (2022). This species grows among rugged limestone rocks which occur at the top of limestone mountain. This habitat is subject to increasing droughts and fires leading to decline of S. chiangdaoensis .

Notes.

Strobilanthes chiangdaoensis resembles S. esquirolii in having oblong-lanceolate bracts and bracteoles. However, the bracts and bracteoles of S. chiangdaoensis are glabrous or sparsely hairy on the adaxial surface and pubescent on the abaxial surface vs. sericeous on both surfaces in S. esquirolii . Moreover, the capsules of S. chiangdaoensis have two seeds with two lower rudimentary ovules vs. four seeds without rudimentary ovules in S. esquirolii .

Figures

Figure 2. Strobilanthes chiangdaoensis Terao A stem and leaves B inflorescences C corolla, side view D corolla lobes, anthers and stigma. Photos taken from cultivated plant from QBG nursery.

Figure 10. Distribution maps of Strobilanthes with capitate inflorescence in Thailand A S. aprica (Hance) T. Anderson, S. articulata J. B. Imlay and S. brandisii T. Anderson B S. capitata (Nees) T. Anderson, S. chiangdaoensis Terao and S. consors C. B. Clarke C S. cruciata (Bremek.) Terao, S. dimorphotricha subsp. rex (C. B. Clarke) J. R. I. Wood and S. echinata Nees D S. erecta C. B. Clarke, S. esquirolii H. Lév. and S. falconeri T. Anderson.