Begonia crassitepala Y.H.Tan & M.B.Maw, 2020

Maw, Mya Bhone, Ding, Hong-Bo, Yang, Bin, Win, Pyae Pyae & Tan, Yun-Hong, 2020, Taxonomic studies on Begonia (Begoniaceae) in Myanmar I: three new species and supplementary description of Begonia rheophytica from Northern Myanmar, PhytoKeys 138, pp. 203-217 : 203

Begonia crassitepala Y.H.Tan & M.B.Maw sp. nov. Figure 4

Diagnosis.

Begonia crassitepala Y.H. Tan & M.B. Maw is morphologically similar to B. dryadis Irmscher (1951: 41) in ovate to broadly ovate leaf, but it can be distinguished by its stem and petiole having white prickles (vs. puberulous), adaxially leaf having densely pinkish or grey hirsute (vs. subglabrous), abaxially outer 2 tepals of pistillate flower and ovary having reddish or whitish succulent strigose and tuberculate (vs. puberulous).

Type.

Myanmar, Kachin State, Putao District, on the way from Ratbaw to Alanga, 27°17'13.73"N, 97°44'24.28"E, 836 m, 15 June 2018, Y.H. Tan, B. Yang, H.B. Ding, X.D. Zeng, M.B. Maw & H.L. Naing M4495 (holotype: HITBC!; isotypes: RAF!).

Description.

Perennial herb, monoecious, rhizomatous. Stem erect, 40-60 cm tall, reddish, densely rusty wooly tomentose, and sparsely covered by whitish soft spine-like hairs, internodes 1-2 cm long. Stipule lanceolate, 1-1.3 × 0.3-0.5 cm, slightly or densely rusty tomentose, deciduous. Leaf petiole 4.5-15 cm, densely rusty tomentose, slightly whitish stiff hairs; blade ovate to broadly ovate, base cordate with overlapping lobes, 12-20 × 15-19.5 cm, asymmetric, adaxiall y green, densely pinkish or grey hirsute, abaxially green, rusty puberulous, venation palmate-pinnate, densely rusty wooly tomentose along midrib and veins, margin denticulate, reddish hirsute along the margin, apex acuminate. Inflorescence nearly terminal, cymose, peduncle 4.4-6.0 cm long, reddish, slightly rusty wooly tomentose and whitish soft spine-like hairs. Staminate flower: pedicel 1.8-2.5 cm long, whitish villose, tepals 4, unequal, outer 2, ovate, 2.2-2.7 × 2.6-2.8 cm, whitish or pinkish with pink lining, thick, ca. 2 mm, inner 2, smaller, 1.7 × 2.1 cm, whitish or pinkish (sometimes with pinkish lining), densely whitish villose on the outer surface; stamen numerous, ca. 200; filaments ca. 2 mm long, fused at base; anther oblong to elliptic, 1-2 mm long. Pistillate flower: pedicel 2.2-2.5 cm, densely whitish or rusty villose, bracteoles absent; tepals 5, equal, obovate, outer 2, 2.0-2.9 × 1.8-2.0 cm, pure white or sometimes with pink lining, densely pinkish or whitish strigose on outer surface, margin entire, inner 3, similar to outer ones but smaller, 1.8-2.1 × 1.6-1.8 cm, ovary 2-locular, placentation axillary, placentae 2 per locule, densely reddish or whitish succulent strigose and tuberculate, styles 2, fused at base, stigma bifid with twisted bands, highly convolute, yellow or golden yellow. Fruit berry-like, elliptic, pale green to pink, 3 wings, unequal, with whitish or reddish succulent strigose and tuberculate (especially on wings).

Phenology.

Flowering from June-July; fruiting from July-August.

Distribution.

Endemic to the type locality, Putao District, Kachin State, Northern Myanmar.

Etymology.

The species epithet refers to its thick tepals.

Ecology.

In the tropical montane forest up to about 577 m elevation, on the moist soil slope.

Conservation status.

Data Deficient (DD). Begonia crassitepala have been collected along the roadside from Langsa to Gawlaw village where no signs of major anthropogenic disturbance were noticed. Further exploration is required to access the current range of the species ( IUCN 2017).

Additional specimens examined

(paratypes). Myanmar. Kachin State: Putao District, along Langsa to Gawlei, tropical montane forest, 27°32'28.94"N, 97°56'36.09"E, 577 m, 2 June 2018, Myanmar Exped. M3952 (HITBC!; RAF!); Kachin State, Putao District, Gathu to Tongwang Cave, 27°29'53.48"N, 97°58'30.84"E, 664 m, 4 June 2018, Myanmar Exped. M4008 (HITBC!; RAF!); Kachin State, Putao District, Gathu to Tangsa, 27°28'41.17"N, 97°56'46.40"E, 550 m, 31 May 2018, Myanmar Exped. M3797 (HITBC!; RAF!); Kachin State, Putao District, Putao Township, Maliraing area, buffer zone of Hkakaborazi National Park, between camp 1 and camp 2, 27°38'03.6"N, 97°22'11.2"E, 552 m, 6 November 2016, Kate et al. 2253 (NY02653741!); Kachin State, Putao District, Naungmung Township, buffer zone of Hkakaborazi National Park, Hill next to Naungmung village, 27°31'02.2"N, 97°50'46.2"E, 845 m, 12 June 2017, Kate et al. 2880 (NY02653917!); Between N Dung Ga and Ting Pru Ting Sar, 27 August 1953, Thar Hla & Chit Ko Ko 4447 (RAF!).

Affinities.

Begonia crassitepala is the most distinct species in the section Platycentrum thanks to its thicken tepals and succulent strigose and tuberculate ovary. The new species shares similar characteristics with B. dryadis in ovate to broadly ovate leaf and 4 tepals of staminate flower. However, it can be easily distinguished by its stem and petiole having rusty tomentose and whitish soft spine-like hairs (vs. puberulous), adaxially leaf having densely pinkish or grey hirsute (vs. subglabrous), adaxially outer 2 tepals of pistillate flower having densely pinkish or whitish strigose (vs. puberulous), ovary having densely reddish or whitish succulent strigose and tuberculate (vs. puberulous).

Figures

Figure 4. Begonia crassitepala Y. H. Tan & M. B. Maw, sp. nov. (photographed by H. B. Ding) A habit B inflorescence C stipule and stem (showing the whitish soft spine-like hairs) D rhizome E single leaf (front view) F single leaf (back view) G hirsute leaf margins H flowers (front view staminate flower) I staminate flower (back view) J dried fruits K pistillate flower (front view) M staminate flower showing 4 tepals N pistillate flower (side view) L capsule and cross section of ovary.