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| Didymocarpus trilobus Souvann. & Phonep., D. laoticus Souvann. & Lanors., D. angustiflorus Souvann. & Lanors., D. bolavenensis Souvann., Soulad. & Phonep., in Souvannakhoummane, Lanorsavanh, Tagane, ... et Lamxay, 2021. Gardens’ Bulletin Singapore. 73(2); |
ABSTRACT
Six new species of Gesneriaceae from Laos, namely Didymocarpus angustiflorus Souvann. & Lanors., D. bolavenensis Souvann., Soulad. & Phonep., D. laoticus Souvann. & Lanors., D. trilobus Souvann. & Phonep., Hemiboea olivifolia Souvann. & Tagane and Paraboea planiflora Souvann. & Lanors., are described and illustrated. Additionally, Aeschynanthus bracteatus Wall. ex A.DC., A. micranthus C.B.Clarke, Epithema ceylanicum Gardner, Lysionotus serratus D.Don, Microchirita luteola C.Puglisi, Paraboea swinhoei (Hance) B.L.Burtt, Petrocosmea kerrii Craib and Pseudochirita guangxiensis (S.Z.Huang) W.T.Wang, are newly recorded for the flora of Laos.
Keywords. Didymocarpus, flora of Laos, Hemiboea, new distribution, new taxon, Paraboea, taxonomy
Didymocarpus angustiflorus Souvann. & Lanors., sp. nov.
Morphologically similar to Didymocarpus payapensis Nangngam & J.F.Maxwell
from Thailand, in habit, elliptic lamina, and glabrous and salverform corolla, but
differs in having lamina abaxially puberulent (vs glabrous), calyx 5-parted to base,
green, with glands outside (vs calyx lobes divided c. 2/3 to the base, maroon, sparsely
covered with multicellular glandular hairs and scattered pigment glands), corolla 1.5–
2.2 cm long, dark blue with white patch in mouth (vs c. 2.5 cm long, dark purple),
filaments sparsely multicellular glandular puberulent (vs glabrous), and style glabrous
(vs sparsely covered with multicellular glandular hairs).
Distribution. Central Laos (known only from the type locality in Phou Khao Khouay
National Protected Area).
Habitat and phenology. Didymocarpus angustiflorus grows on moist rocks in
evergreen forest, along with Globba sp., Monolophus sp. (Zingiberaceae), Sonerila sp.
(Melastomataceae), Begonia hymenophylla Gagnep. (Begoniaceae) and some ferns.
Flowering from July to August and fruiting from September to October (observed
from cultivation).
Etymology. The specific epithet refers to its narrow cylindrical corolla tube.
Vernacular name. ດອກແກຫຼອດມ່ວງ (Dok Kea Loth Mouang).
Didymocarpus bolavenensis Souvann., Soulad. & Phonep., sp. nov.
Morphologically similar to Didymocarpus inflatus J.F.Maxwell & Nangngam from
Thailand, in habit, ovate lamina, campanulate glabrous calyx, and cylindric ovary,
but differs in the salverform to narrowly funnelform corolla which is 3–3.5 cm long,
lobes purple with white lines in the mouth (vs funnelform, 4 cm long, lobes violet
with dark violet-reddish lines in mouth), and broadly reniform corolla lobes (vs lobes
suborbicular).
Distribution. Southern Laos (so far known only from the Bolaven Plateau).
Habitat and phenology. Didymocarpus bolavenensis grows on a wet and shaded table
rock located near a stream in lower montane evergreen forest. The surface of the rock
is covered with humus formed from mosses and ferns. Flowering from August to
September and fruiting from September to November.
Etymology. The specific epithet of this taxon refers to the type locality.
Vernacular name. ດອກແກມ່ວງບໍລະເວນ (Dok Kea Mouang Bolaven).
Didymocarpus laoticus Souvann. & Lanors., sp. nov.
The new species is morphologically similar to Didymocarpus sinoindicus N.S.Prasanna,
Lei Cai & V.Gowda in habit, ovate lamina and ovary shape, but differs in having calyx
10–13 mm long, white, glabrous (vs 4–6 mm long, cream-white to greenish yellow,
covered with peltate pigment glands outside), corolla 30–32 mm long, white with dark
blue in the mouth (vs corolla 8.5–12 cm long, cream-white to greenish yellow with
purple striations in the mouth), and ovary glabrous (vs ovary covered with peltate
pigment glands).
Distribution. Central Laos (Phou Khao Khouay National Protected Area in Bolikhamxai
Province).
Habitat and phenology. It was found growing on wet rocks near a small stream in
mixed deciduous forest where Dendrocalamus membranaceus Munro (Poaceae) is
dominant. Flowering from late July to August.
Etymology. The specific epithet refers to where the type material was collected.
Vernacular name. ດອກແກຂາວໃຈຟ້າ (Dok Kea Khao Jai Fa).
Didymocarpus trilobus Souvann. & Phonep., sp. nov.
The new species is morphologically similar to Didymocarpus albiflorus Souvann.
& Phonep., in having corolla funnelform, but differs in often lacking larger basal
leaves (vs with larger basal leaves in D. albiflorus), calyx campanulate and 3-lobed
(vs funnelform and 5-lobed), corolla dark purple (vs white), and ovary glabrous (vs
sparsely glandular puberulent).
Distribution. Central Laos (so far known from two small populations in Phou Khao
Khouay National Protected Area, in Vientiane and Bolikhamxai).
Habitat and phenology. It is common in seasonal deciduous forest mixed with
bamboo at an altitude of 300 m and grows on wet rocks with mosses and Adiantum sp.
(Adiantaceae). Flowering from July to August and fruiting from August to October.
The above-ground part of the plants dries up completely in January (recorded from
cultivated living collection).
Etymology. The species epithet of this taxon refers to the three lobes of the calyx due
to the upper lobes fusing into a single lobe.
Vernacular name. ດອກແກມ່ວງໃຫຍ່ (Dok Kea Mouang Yai).
Hemiboea olivifolia Souvann. & Tagane, sp. nov.
Morphologically similar to Hemiboea cavaleriei H.Lév., but differs in having lamina
succulent and dark waxy olive-green adaxially, and corolla white and glabrous outside
(vs lamina herbaceous in H. cavaleriei var. cavaleriei, lamina papery to thinly papery
in H. cavaleriei var. paucinervis W.T.Wang & Z.Y.Li and both varieties non-waxy
olive-green on adaxial surface; corolla outside pale yellow and sparsely glandular
puberulent).
Distribution. Northern Laos (Pha Nam Yard Forest Reserve Area, Louangphabang
Province).
Habitat and phenology. It grows on a limestone hill in deciduous forest, c. 300 m from
the banks of the Mekong River, where the stable humidity, essential for the survival of
this species, comes from the river. It occurs with Amorphophallus yunnanensis Engl.
(Araceae), Impatiens parishii Hook.f. (Balsaminaceae), Dracaena sp. (Asparagaceae)
and Asplenium sp. (Aspleniaceae). Flowering from October to November and fruiting
in December.
Etymology. The specific epithet of this taxon refers to the olive-green upper leaf
surface.
Vernacular name. ດອກລະຄັງເງິນ (La Khang Ngeurn).
Paraboea planiflora Souvann. & Lanors., sp. nov.
Morphologically similar to Paraboea khaoyaica Kaitongsuk et al. in habit and in
having an almost flat-faced corolla (Kaitongsuk et al., 2021), but differs in bracts
broadly oblanceolate to oblong, calyx with a scattered glandular indumentum, and
corolla minutely pubescent outside (vs bracts linear or lanceolate, calyx glabrous, and
corolla glabrous in P. khaoyaica).
Distribution. Central Laos (Phou Khao Khouay National Protected Area, in
Bolikhamxai and Saysomboun Province).
Habitat and phenology. Paraboea planiflora grows on open to semi-shaded rocks in
mixed deciduous forest with bamboo, and is often common near streams. Flowering
from July to August and fruiting from August to September.
Etymology. The specific epithet of this taxon refers to the flat-faced corolla.
Vernacular name. ຊາລຶສີ (Sa Leu Si).
Keooudone Souvannakhoummane, Soulivanh Lanorsavanh, Shuichiro Tagane, Phetlasy Souladeth, Phongphayboun Phonepaseuth, Wittaya Pongamornkul and Vichith Lamxay. 2021. Six New Species and Eight New Records of Gesneriaceae from Laos. Gardens’ Bulletin Singapore. 73(2); 427 - 456.
