Amomum schistocalyx Y.H.Tan & H.B.Ding, 2020

Ding, Hong-Bo, Yang, Bin, Maw, Mya Bhone, Win, Pyae Pyae & Tan, Yun-Hong, 2020, Taxonomic studies on Amomum Roxburgh s. l. (Zingiberaceae) in Myanmar II: one new species and five new records for the flora of Myanmar, PhytoKeys 138, pp. 139-153 : 139

Amomum schistocalyx Y.H.Tan & H.B.Ding sp. nov. Fig. 1

Diagnosis.

Amomum schistocalyx Y.H. Tan & H.B. Ding is similar to A. putrescens D. Fang (1978: 51) in having lax inflorescence, similar yellow flowers, non-tubular bracteoles and green fruits, but can be distinguished by its leaves abaxially densely appressed silvery pubescent (vs. glabrous leaves), 2-cleft ligule (vs. entire ligule), non-tubular calyx (vs. tubular calyx), epigynous glands 2 mm (vs. 5 mm).

Type.

Myanmar. Sangaing Region, Hkamti District, near Htamanti village. 95°22'40.42"E, 25°22'32.40"N; 135 m elev., 3 June 2019, Y.H. Tan & H.B. Ding M5785 (holotype: HITBC!; isotypes: RAF!).

Description.

Clump-forming herb, 1.0-2.0 m tall. Pseudostem with 2-7 leaves per pseudostem, swollen at base, greenish yellow or brownish yellow; ligule ovate, 2-lobed to middle or bottom, 2.0-4.0 cm long, yellowish brown, membranous, fragile, pubescent, apex acute; petiole 2.0-7.0 cm; leaf blade adaxially green, abaxially silvery, elliptic to oblong-lanceolate, 17-50 × 6-10 cm, adaxially glabrous, abaxially densely appressed silvery pubescent, base attenuate, apex caudate. Inflorescence radical, 5.0-18.0 cm, arising from the rhizome, one inflorescences per pseudostem, peduncle 4.0-10.0 cm, reddish-brown, flowering part obpyramidal, 3.6-5.5 × 3.5-4.5 cm, lax with rachis visible between bracts, sterile bracts ovate, 1.6-2.7 × 1.5-2.0, yellowish brown, membranous; fertile bracts (bracteoles), non-tubular, lanceolate, 1.5-2.5 × 0.3-0.5 cm, yellowish brown, membranous, striate then soon rotting, subtending a single flower. Flowers 3.2-4.0 cm, yellow. Calyx non-tubular, split to bottom (even when flower budding), 1.0-1.5 × 0.3-0.6 cm, apex 3-toothed, membranous, yellowish brown, pubescent. Floral tube 1.0-1.2 cm long, ca. 0.4 cm wide at mouth, pale yellow, glabrous; dorsal corolla lobe oblong or ovate, 1.5-1.7 × 0.5-0.7 cm, brownish yellow and reddish towards apex, apex cucullate with a 1-2 mm long cusp, margin ciliate; lateral corolla lobes oblong, 1.5-1.7 × 0.4-0.5 cm, white towards base and brownish yellow at apex, apex rounded, margin ciliate. Labellum spreading, with red at claw, dull brownish yellow at middle and margin, obovate, entire, 1.9-2.3 × 1.0-1.2 cm, margin crisped, prominently veined, dentate, glabrous, adaxial surface pilose at base. Lateral staminodes lanceolate, adaxial surface red towards base and brownish yellow at apex, abaxial surface brownish yellow, 3-4 mm. Stamen 1.2-1.7 cm long, filament 0.4-0.7 × 0.2-0.3 cm, red at base, brownish yellow at apex, pubescent, connective pubescent, brownish yellow, anther thecae oblong, 0.7-0.9 cm long, creamy-white, dehiscing throughout their length, anther crest semi-lunar or inconspicuous trilobed, ca. 7 × 2 mm, brownish yellow, membranous, margin dentate. Epigynous glands two, oblate, ca. 2 × 1 mm, creamy, glabrous. Ovary ellipsoid, ca. 6 × 3 mm, villous; style ca. 2.7 cm long, puberulous; stigma cup-shaped, white, mouth ciliate. Infructescence up to 40 cm long, usually with 1-7 fruits reaching maturity. Capsule ovoid, 3.0-3.5 × 2.7-3.0 cm, 9-winged, green, at apex with persistent pubescent calyx, wings straight, stalk 5-7 mm.

Phenology.

Flowering maybe in April-June and fruiting in May-July.

Distribution.

Known only from the type locality, beside the Chindwin River, Hkamti District, Sangaing Region, Myanmar.

Ecology.

On the riverside at an elevation of 100-150 m in tropical forest.

Etymology.

The specific epithet ' schistocalyx ' refers to the non-tubular, dehiscent calyx.

Conservation status.

LC. This species is locally common. Populations in Htamanti Wildlife Sanctuary are well protected. The populations near Htamanti village are not in a protected area but the populations are robust. So we treat this species as of Least Concern ( IUCN 2017).

Affinities.

Amomum schistocalyx Y.H. Tan & H.B. Ding shares similar characters with A. putrescens but differs in many characters, such as leaves (abaxially densely appressed silvery pubescent vs. abaxially glabrous, respectively), ligule (2-cleft vs. entire, respectively), calyx (non-tubular vs. tubular, respectively), labellum (red at claw, dull brownish yellow at middle and margin vs. almost pure yellow, respectively), lateral staminodes (lanceolate, adaxial surface red towards base and brownish yellow at apex, abaxial surface brownish yellow vs. tooth like, red, respectively) and epigynous glands (2 mm vs. 5 mm, respectively).

Additional specimens examined (paratypes).

Myanmar. Sangaing Region, Hkamti District, Htamanti Wildlife Sanctuary, near Nam E Zu, Camp 1. 95°28'20.56"E, 25°32'13.42"N, 141 m elev., 20 May 2019, fruiting, B. Yang, H.B. Ding & X.D. Zeng M5158 (HITBC!; RAF!); Sangaing Region, Hkamti District, Htamanti Wildlife Sanctuary, near Nam E Zu, Camp 2. 95°31'34.08"E, 25°30'40.15"N, 143 m elev., 25 May 2019, fruiting, Y.H. Tan, M. Deng, B. Yang, H.B. Ding & X.D. Zeng M5374 (HITBC!; RAF!).

New records for Myanmar

Figures

Figure 1. Amomum schistocalyx Y. H. Tan & H. B. Ding, sp. nov. A habit B leaf blade abaxially C, D ligule E pseudostem F flowers (front view) G flowers (back view) and showing non-tubular calyx (even when flower budding) H inflorescence I infructescence J single flower K single fruit L cross section of fruit M bracteole N calyx O dorsal corolla lobe P lateral corolla lobes Q labellum with floral tube and lateral staminodes R stamen with stigma and style (back view) S stamen with stigma and style (front view) T ovary with pedicel U epigynous glands. Photographed by H. B. Ding.