Globba larsenii Sangvir. & M.F.Newman, 2021

Sangvirotjanapat, Sunisa & Newman, M. F., 2021, Eight new species of Globba (Zingiberaceae) from Thailand and Lao PDR, Phytotaxa 505 (2), pp. 139-156 : 145-147

Globba larsenii Sangvir. & M.F.Newman , sp. nov. (Subgenus Globba )

Similar to Globba expansa Wall. ex Horan. ( Fig. 2A , Table 2) in its medium to large size of leafy stem, erect inflorescence with caducous bracts, and four-appendaged flower but differing by its perfect flowers (vs. plant andromonoecious), yellow bracteoles (vs. green bracteoles), and globose fruits with shallow ridges (vs. cylindrical with deep ridges).

Type: THAILAND, Bueng Kan, Phu Wua, Tham Phra , 18º 8’16’’N, 103º59’45’’ E, 200 m, 6 August 2015, Middleton D. J., Hemrat C., Karaket P., Suddee S. & Triboun P. 5939 (holotype BKF!, isotypes AAU!, E! [ E00955838 ], QBG!) Fig. 4 .

Herb, 30–80 cm tall. Leaf sheaths 4–5 bladeless, minutely hairy, green; blades 6–7, elliptic, 8–15 × 2–3 cm, base obtuse, apex acuminate, glabrous below, sparsely pubescent above, shiny dark green above; petiole to 5 mm long; ligule shallowly bilobed, c. 2 mm long, glabrous. Inflorescence erect, lax, secund, 6–18 × 4–8 cm; peduncle 1–2 cm long, brown-red; rachis glabrous, base brown-red, tip green, glabrous; bracts not seen; bracteoles caducous, elliptic or ovate, 4–5 × 2–3 mm, keeled, apex mucronate, yellow; cincinni 1–2 cm long, flowers crowded at tip of cincinni, brown-red or green. Flowers 3–3.4 cm long, yellowish orange; ovary ellipsoid, c. 3 × 1.5 mm, shallowly ridged, green; style filiform; stigma cup-shaped, ostiole ciliate; calyx infundibuliform, 3–4 mm long, unequally trilobed with acute apices, yellow; floral tube c. 14 mm long, hairy; dorsal corolla lobe narrowly elliptic, 5–6 × 1–2 mm, hooded, apex obtuse, yellowish orange; lateral corolla lobes narrowly elliptic, 3–5 × 1.5–2 mm, hooded, apex obtuse, yellowish orange; lateral staminodes obliquely elliptic or oblong, c. 15 × 5 mm, apex obtuse; labellum obtriangular, c. 10 × 5 mm, base truncate, apex bilobed, lobes acute, spot absent, yellowish orange; nectar tube c. 4 mm long; stamen: filament c. 25 mm long, yellow; anther elliptic, c. 2 × 1 mm, connective tissue and appendages orange, semitransparent; appendages 4, bifid, upper pair bigger, lower pair about half length of upper pair, triangular, c. 3 × 1 mm, apex acuminate, curved. Fruit globose, c. 5 mm in diameter, trisulcate, smooth, green; seeds not seen. Bulbils produced along peduncle or within leaf sheaths, ovoid, c. 5 × 3 mm, corky.

Etymology: This species honours Prof. Kai Larsen (1926–2012), Danish botanist, professor of the Department of Systematic Botany, University of Aarhus and co-founder of the Flora of Thailand project who dedicated his life to the study of Thai plants. He specialised in Thai Zingiberaceae and published several papers on Globba .

Distribution: Endemic to Thailand. Both Thai provinces in which Globba larsenii has been found border Lao PDR so it is to be expected there too.

Proposed IUCN conservation status: Least Concern (LC). Globba larsenii has been collected twice in Phu Langka National Park, in 2001 and 2020, and once in Phu Wua Wildlife Sanctuary in 2015. It is locally common, more than 500 mature individuals in each population. As both subpopulations are entirely within protected areas where there is no identifiable threat, this species is assessed as of Least Concern.

Ecology: Growing on sandstone bedrock in shade.

Specimen examined: Nakhon Phanom: Ban Phaeng district, Phu Langka National Park, 190 m, 30 August 2020, Tetsana et al. 1843 ( BKF); ibid., Tad Kham Falls , 150 m, 25 August 2001, Pooma et al. 2666 ( BKF, L) .

Notes: Globba larsenii is recognised by its brown-red rachis which contrasts with the yellow flowers. As in the case of Globba mollis , this is a species that shows some of the characters of section Nudae subsection Nudae but two floral morphs and globose fruit are not present so it is classified only to subgenus for now.

Figures

FIGURE 2. A. Globba expansa Wall. ex Horan. B. G. leucantha Miq. C. G. nisbetiana Craib. Photographs by S. Sangvirotjanapat.

FIGURE 4. Globba larsenii Sangvir. & M.F.Newman (Sangvirotjanapat sn) A. Habitat B. Inflorescence C. Leaf D. Bracteoles E. Flower, front view F. Flower dissection; lcl = lateral corolla lobe, dcl = dorsal corolla lobe, ls = lateral staminode, lb = labellum, at = anther thecae G. Fruit. Scale bars: B & C = 5 cm; E & F = 1 cm; G = 5 mm. Photographs by S. Sangvirotjanapat.