Garcinia yaatapsap K. Armstr. & P.W. Sweeney, 2022

Sweeney, Patrick W., Nwe, Thet Yu & Armstrong, Kate E., 2022, Garcinia yaatapsap (Clusiaceae), a new species from northern Myanmar, Phytotaxa 545 (2), pp. 121-127 : 123-125

Garcinia yaatapsap K. Armstr. & P.W. Sweeney , sp. nov. ( Figs. 1–2 )

Type: — MYANMAR. Sagaing Region: Hkamti District, Hkamti Township, Htamanthi Wildlife Sanctuary , Just upstream from Nam Eizu camp 1,184 m. a.s.l., 25.537833°, 95.465861°, 11 September 2016, K. Armstrong, D. Daly, P. P. Hnin, T. Y. Nwe, L. Zaw, K. Z. Aung, H. Aung 1406 (holotype NY [ NY02654830 ]!; isotypes E!, RAF!) .

Diagnosis: — Garcinia yaatapsap is similar to G. stipulata T.Anderson in Hooker (1874: 267) and G. nujiangensis C.Y.Wu & Y.H.Li in Li (1981: 494), but branchlets distinctly 4-sided and winged on angles (particularly distally) (vs. terete); leaf bases subcordate to cordate (vs. cuneate); leaves nearly sessile, petiole length to leaf blade length ratio smaller (ca. <1:25 vs.>1:16).

Description: —Dioecious, evergreen tree to ca. 12 m tall; exudate yellow; branchlets distinctly 4-sided, winged on angles (particularly distally), 6–8 mm wide at distal internode, glabrous. Leaves opposite, subsessile (petiole to lamina length ratio = 0.024 –0.040); lamina dark green adaxially, whitish-green abaxially in vivo, blades narrowly to broadly elliptic, 20.5–34 cm long × 7.5–14 cm wide, coriaceous, glabrous, base subcordate to cordate, sometimes clasping the stem, decurrent onto petiole ca. 5 mm, margin entire and finely revolute, apex acute to acuminate, acumen 10–15 mm long; venation brochidodromous; midrib raised adaxially and abaxially, more so abaxially, secondary veins 16–20 pairs per side, curved, impressed adaxially, prominently raised abaxially, forming an intramarginal vein loop 1–2.5 mm from the margin; intersecondary veins usually absent; tertiary venation percurrent; exudate-containing canals conspicuous abaxially (not visible adaxially); stipuliform structures triangular, ca. 1.5 cm long × 1 mm wide, marcescent at older branchlet nodes; petioles 5–14 mm long, ca. 5 mm wide, with two longitudinal ridges on adaxial surface, sometimes reddish in vivo, glabrous. Inflorescences axillary, lax, cymose, 3–5-flowered, ca. 2 cm long × 3.5 cm wide; peduncles ca. 6 mm long × 1.2 mm wide, angled, glabrous; pedicels 5–17 mm long × 0.6–1 mm wide, glabrous; bracts at apex of peduncle ca. 1.2 mm × 1.2 mm, broadly triangular-ovate, glabrous, bracts in branched portion of the inflorescence ca. 1 mm × 1 mm, broadly triangular-ovate, glabrous. Staminate flowers 4-merous, ca. 1 cm long × 1.5 cm wide; sepals free, imbricate, broadly ovate to orbicular, convex and keeled, ca. 8 mm long × 8 mm wide (inner pair slightly larger), light yellowish-green, glabrous; petals free, imbricate, broadly elliptic, convex and keeled, ca. 15 mm long × 8 mm wide, light yellowish-green, glabrous, exudate-containing canals conspicuous when dry, margin entire; androecium with ca. 200 stamens united into an annular mass encircling and attached to the pistillode, anthers suborbicular, ca. 0.5 mm × 0.5 mm, sessile; pistillode short-stalked, stigma capitate, ca. 3 mm diameter, vivid yellow; united androecium and pistillode on stalk ca. 4.5 mm long × 8 mm wide. Carpellate flowers not observed. Fruits (immature?) 2-locular, baccate, ellipsoid, ca. 4 cm long × 1.8 cm wide, green with brown suberized areas, smooth, outer-whorl of 2 sepals persistent; stigmas slightly raised, brown, concave-discoid, margin revolute, slightly irregular; pedicel ca. 1.5–1.75 cm long. Seeds two, ellipsoid, ca. 2 cm long × 1 cm wide; testa brown, exudate canals present.

Additional Specimens Examined (paratypes): — MYANMAR. Sagaing Region: Homalin Township, Basin of Chindwin River, Htamanthi Wildlife Sanctuary, Nam Khwe Daing area , along Nam Khwe Daing stream, 123 m. a.s.l., 25.1883°, 95.2345°, 27 October 2014, Phyu Phyu Hnin et al. 62 ( E, NY NY02648440 , RAF, TNS, YU) ; Sagaing Region, Hkamti District, Homalin Township , Htamanthi Wildlife Sanctuary, Nam E Paw stream, above confluence with the Nam Khwe Daing stream, 165 m. a.s.l., 25.203722°, 95.284028°, 3 April 2018, Kate Armstrong et al. 3716 ( E, NY, RAF, TNS, YU) ; Sagaing Region, Hkamti District, Homalin Township, Nam Sa Bi village , 129 m. a.s.l., 25.360806°, 95.342833°, 6 March 2019, Kate Armstrong et al. 4354 ( NY, RAF, YU) .

Distribution and Habitat: — Garcinia yaatapsap has only been collected four times in the vicinity of Htamanthi Wildlife Sanctuary ( Fig. 3 ) and is likely to be endemic to this area of the upper Chindwin Basin. This species occurs from 123-184 m a.s.l. in the Kachin-Sagaing low elevation evergreen subtropical rainforest ecosystem ( Armstrong et al. 2020; Murray et al. 2020), which is a lowland (ca. 100-300 m a.s.l.) evergreen closed forest ecosystem in northern Myanmar, where there is abundant rainfall (2,000+ mm) and generally moist conditions.

Etymology: —The specific epithet “yaatapsap” is the Shan-ni (Red Shan) vernacular name for the plant, which translates as “medicine to join the liver [back together]”. This epithet is constructed as a noun in apposition. Locally, a tea made from Garcinia yaatapsap is used as tonic for repairing a damaged liver due to drinking excess alcohol.

Proposed IUCN Conservation Status: — Garcinia yaatapsap is expected to be endemic to the upper Chindwin River Basin in and around Htamanthi Wildlife Sanctuary. Based on currently available specimen data its Extent of Occurrence (EOO) is 88 km 2 and Area of Occupancy (AOO) is 16 km 2 as calculated using GeoCAT ( Bachman et al. 2011). Thus, it is assessed as being Endangered [B2a, biii,iv,v] based on AOO, due to its occurrence in a small area, the low number of mature individuals observed, and its popular local use as a medicinal plant ( IUCN 2019).

Figures

FIGURE 1. Garcinia yaatapsap. A. Branch with staminate flowers. B. Apex of branch showing leaf bases, young leaves, and stipuliform structures. C. Part of staminate infloresence. D. Staminate flower. E. Cross section of androecium and pistillode with close-up views of stamens and an anther. F. Branch with fruits. G. View of abaxial leaf surface. Illustration by Bobbi Angell.

FIGURE 2. Garcinia yaatapsap. A. Apex of branch showing leaf bases, young leaves, and stipuliform structures (indicated by arrow). B. Staminate flowers. C. Branch with fruits. D. Branch with leaves. Scale bars: A, B = 5 mm, C = 1 cm, D = 2 cm.

FIGURE 3. Distribution of Garcinia yaatapsap.