| Original Botanical Description or Link to | Two new species of Begonia L. (Begoniaceae) from central Laos
Keooudone SOUVANNAKHOUMMANE, Soulivanh LANORSAVANH, Vichith LAMXAY: Begonia hinnamnoensis Souvann & Lanors., sp. nov.
Som Koung Khan Khak [Bufo begonia] Sect. Diploclinium.
Differs from the allied Begonia gesneriifolia Aver.
in having a denser indumentum over all vegetative parts
and fruit wings narrowly triangular (B. gesneriifolia has
short scurfy hairs, sub-glabrous petioles, glabrous leaf
lamina, inflorescenceand flowers, and fruit wings
distinctly larger). Also differs from Begonia cladotricha
M. Hughes in having a stout rhizome, upper surface of
lamina bullate between veins giving a rugose appearance
and pistillate flowers smaller fruit wings (B. cladotricha
has tuberous rhizome, upper surface of lamina not
bullate between veins and pistillate flowers larger fruit
wings). − Type: Laos, Khammouan province, Boualapha
district, Hin Nam No National Protected Area,
17°27'24.4"N 105°46'13.1"E, 240 m, 9 October 2017,
Lamxay et al. HNN 227 (holo HNL, iso FOF, E, SING).
Monoecious rhizomatous herb, 24–30 cm tall.
Rhizome stout, c. 5–12 cm long, c. 5–8 mm in diam.,
erect near apex, c. 1.2 cm tall, with numerous fibrous
roots. Leaves arranged in rosette-like cluster at the apex
of rhizome; petiole 1.5–9 cm long, branched ginger
hairs, fleshy, pale green to brown; lamina succulent,
symmetrical, reniform, 2.4–6.8 × 3.2–9 cm, base
shallowly cordate, apex rounded, margin crenate to
undulate; adaxial surface lime green to olive green with
sometime grey-white splotch, bullate between veins
giving lamina a rugose appearance, abaxial surface pale
green to brown, branched ginger hairs on both of surface;
venation palmate, veins 6–9, prominent beneath.
Stipules persistent, membranous, lanceolate to
triangular, 8–22 × 4–12 mm, apex acuminate to caudate,
margin entire, outside surface branched ginger hairs,
inside surface glabrous, pink to lightly green.
Inflorescences compound cymes arising from top of
rhizome, branched up to 4 times, bisexual, 25–35 cm
long, staminate flowers distal and pistillate flowers
basal, protandrous; peduncles 23–30 cm long, terete,
branched ginger hairs, lightly brown to red. Bracts ovate
to triangular, 4–8 × 1.5–2.5 mm, apex acute, margin
entire, branched ginger hairs on outside surface, pale
green to brown. Staminate flowers: pedicels 5–9 mm
long, erect or occasionally ascending, with sparse
branched ginger hairs, red; tepals 4, outer pair ellipticobovate,
7–12 × 3–5 mm, apex obtuse to rounded,
outside surface with sparse branched ginger hairs, inside
surface glabrous, pale pink to white, inner pair narrowly
elliptic, 3–4.5 × 1–1.8 mm, apex rounded, glabrous, pale
pink to white; stamens c. 19, bright yellow, filaments
clustered at the base, c. 0.3 mm long, free 0.5–1 mm
long, anthers oblong-elliptic, 0.3–0.6 mm long,
dehiscing by longitudinal slits near the tip. Pistillate
flowers: pedicels 9–15 mm long, with branched ginger
hairs, red; tepals 5, outer 2, oblanceolate-obovate, 6–11
× 4–8 mm, apex obtuse to rounded, outside branched
ginger hairs, inner 3 unequal, obovate, 4–10 × 2.5–6 mm,
apex rounded, glabrous, same colour as staminate
flower; ovary lightly green to pale pink, with 3 subequal
wings; 3-locular, placentation axillary, 2 branches per
locule; styles 3, fused at the base, dark yellow, stigmatic
band U-shaped and minutely papillose. Fruits capsules,
subglobose, 4–7 × 3.5–6.8 mm; locules subglobose, 2.0–
2.5 × 2.2–2.7 mm, wings triangular, c. 5 mm long, 2–3
mm wide at base, with branched ginger hairs, pale green
to pink, drying pale brown. Seeds numerous, ellipticoblong,
0.3–0.4 × c.0.1 mm, testa reticulate, brown.
Distribution. Endemic to Khammouan province,
Boualapha district, Hin Nam No National Protected Area,
only know from type locality.
Habitat and ecology. Occurring on limestone rock
crevices in seasonally dry evergreen forest at 240 m
elevation. Flowering September to October; fruiting
October to January.
Notes. Begonia hinnamnoensis is closely allied with
B. cladotricha and B. gesneriifolia, as shown by
characters of reniform lamina and pistillate flowers with
5-tepals. The basally-branched hair type of this species
is the same as in B. cladotricha (Hughes, 2008b). The
specific epithet hinnamnoensis refers to the type locality.
Proposed IUCN category. VU D1. This new taxon
is restricted to karst limestone and known only from the
type locality in Hin Nam No National Protected Area. |
