Blumea htamanthii Y.L.Peng, C.X.Yang & Y.Luo, 2020

Peng, Yulan, Yang, Chenxuan & Luo, Yan, 2020, Blumea htamanthii (Asteraceae), a new species from Myanmar, PhytoKeys 138, pp. 225-232 : 225

Blumea htamanthii Y.L.Peng, C.X.Yang & Y.Luo sp. nov. Figs 1 , 2

Diagnosis.

This new species is the most similar to Blumea bifolia (Linn.) DC. in its obovate-oblong leaves, reflexed linear phyllaries, flat, alveolate, glabrous receptacles. However, it is distinguished by its leaf blades with papillary hairs and sparse multicellular villous, abaxial purple, 1-4 capitula at the ends of the peduncles and its unribbed achenes.

Type.

Myanmar: Htamanthi Wildlife Sanctuary, Hkamti District of Sagaing Region, the cliff near the edges of the forest along the branch river of Chindwin River, elevation 127 m, 25.4948593°N, 95.4319749°E, May 23 2019,Y.L. Peng, C.X. Yang & Y. Luo, SE02614 (Holotype CDBI!, Isotype HITBC!, RAF!).

Description.

Annual herbs, herbaceous, 5-25 cm tall. Stems erect, occasionally procumbent, villous with multicellular hairs, leaves basal rosette or sub-basal rosette and a few cauline, petioles 0.2 to 0.3 cm long, at the base of petioles with white pilose hairs, lamina obovate or obovate-oblong, thinly papyraceous, 0.9-3.5 × 0.3-1.2 cm, acute at the apex, base abruptly constricted into winged petiole, margins distantly dentate, villous with multicellular hairs, both surfaces hairy, significantly discoloured, upper surface bright green, leaf blade with papillary hairs and sparse multicellular pilose, multicellular pilose on the veins are dense, lower surface purple, the base of margins serrate, apex acute; inflorescences loose panicles, 3-10 cm long, capitula terminal, rarely axillary, 1-4 heads at the ends of the peduncles, 4-6 mm in diameter, peduncles 5-25 mm long with white pilose hairs; phyllaries herbaceous, slightly longer than the florets, 10-20 mm long, phyllaries in 5 (-6)-seriate, reflexed, outer phyllaries linear, with colleters and pilose hairs, lower part of the inner phyllaries lanceolate, upper part abruptly reduced to a linear tip, the middle and upper part margin of the inner phyllaries lacerate, with sparse multicellular hairs, receptacle 0.5-1 mm in diameter, flat or slightly convex, alveolate, glabrous. Florets yellow, tubular, glabrous; those of the bisexual florets, corolla tube 3.5-4.5 mm long, with 5 ovate, papillate lobes, styles of the hermaphroditic flowers are wrapped in a slightly longer stamen tube; those of the female florets are filiform, up to 3.5 mm long, with 2 to 3 lobed, corolla tube 1-1.5 mm long. Cypselas pale brown, oblong, pubescent, not ribbed, 0.4-0.6 mm long, pilose; pappus carducous, white, 3-4 mm long.

Etymology.

The new specific epithet “htamanthii” refers to the name of the town along the Chindwin River, Hkamti District of Sagaing, Myanmar, where the novel species was discovered.

Phenology.

Flowering and fruiting April to June.

Distribution and habitat.

Myanmar. Sagaing, Htamanthi; Blumea htamanthii is only known from the type collection along the branch river of Chindwin River, growing on the steep rocks near the forest from 66-366 m altitude above mean sea level, 25.4948°-25.5152°N, 95.4319°-95.5268°E in the Htamanthii Nature Reserve.

Additional material examined.

25.4947931°N, 95.4319147°E, elevation 121-129 m, 23 May 2019,Y.L Peng, C.X. Yang &Y. Luo SE02645, SE02694 (CDBI, HITBC, RAF); 25.5132139°N, 95.5269449°E, elevation 36-367 m, 26 May 2019, Y.L. Peng, C.X. Yang & Y. Luo SE02730, SE02731, SE02736 (CDBI, HITBC, RAF); 25.5127053°N, 95.5267582°E, elevation 366 m, 27 May 2019, Y.L Peng, C.X. Yang & Y. Luo, SE02769 (CDBI, HITBC, RAF); 25.5128305°N, 95.5268144°E, elevation 366 m, 27 May 2019, SE02770 (CDBI, HITBC, RAF), 25.5133152°N, 95.5262927°E, elevation 340 m, 27 May 2019, Y.L Peng, C.X. Yang & Y. Luo SE02777 (CDBI, HITBC, RAF); 25.5128089°N, 95.5266037°E, elevation 160 m, 27 May 2019, Y.L Peng, C.X. Yang & Y. Luo SE02806, SE02861(CDBI, HITBC, RAF).

Discussion.

Blumea htamanthii resembles B. bifoliata (Linn.) DC. and B. diffusa R. Br. ex Benth. in its reflexed linear phyllaries, flat, alveolate, glabrous receptacle and obovate leaves. Blumea htamanthii differs from B. bifoliata by erect stem and basal bicolour rosette leaves, abaxially purple, with short petioles, leaf blade with papillary hairs and sparse multicellular villous and 1-4 capitula at the ends of the peduncles, achenes not ribbed (vs. leaves sessile, one colour, villous with multicellular hairs and stipitate glands, solitary capitula, achenes 6-10 ribbed) (Table 1 ). Blumea htamanthii differs from B. diffusa in erect stems and leaves with short petioles, cauline leaf base not amplexicaulous, and 1-4 capitula at the ends of the peduncles (vs. stems procumbent, leaves sessile, one colour, cauline amplexicaulous, solitary capitula) (Table 1 ). In addition, B. bicolor is endemic in the Philippines with abaxially purple leaves ( Merrill 1912, Randeria 1960). However, it is a tall erect herb with leaves aggregated in the middle portion of the stem, leave blade oblong elliptic, 5.5-23.5 × 1.3-8.6 cm and achenes ribbed. Its morphological traits are significantly different from those of B. htamanthii (Table 1 ).

Key to Blumea species in Myanmar (including the closely related species B. bicolor in the Philippines and B. diffusa in Australia)

Figures

Figure 1. Blumea htamanthii Y. L. Peng, C. X. Yang & Y. Luo, sp. nov. A habit B the inner phyllary C the outer phyllary D bisexual floret E female floret F style of bisexual floret G magnified part of upper surface of the leaf. Drawings: Jian Gu based on the holotype.

Figure 2. Blumea htamanthii Y. L. Peng, C. X. Yang & Y. Luo, sp. nov. in the field and magnified leaves and receptacle A the whole plant B inflorescences C the abaxial surface of the leaf D receptacle E the upper surface of the leaf F magnified part of upper surface of the leaf G basal leaves. Photos: Y. L. Peng.