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| Middletonia gebosa C.Puglisi: A. Habit, showing young fruit; B. Flowers; M. reticulata (Barnett) C.Puglisi: D. Habit; E. Flowers.
Photographs by Preecha Karaket (A, C–E) and David Middleton (B).
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ABSTRACT
The genus Middletonia in Thailand is revised. We recognise four species, including the newly described Middletonia glebosa C.Puglisi and the resurrected M. reticulata (Barnett) C.Puglisi. A key to the species, full descriptions and proposed conservation assessments are provided.
KEYWORDS: taxonomy, new species, Flora of Thailand
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| Figure 1. Middletonia gebosa C.Puglisi: A. Habit, showing young fruit; B. Flowers; M. reticulata (Barnett) C.Puglisi: D. Habit; E. Flowers.
Photographs by Preecha Karaket (A, C–E) and David Middleton (B).
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MIDDLETONIA C.Puglisi,
Taxon. 65: 286. 2016.
Type species:
Middletonia multiflora (R.Br.) C.Puglisi.
Five species, found in India, Bangladesh,
Bhutan, Myanmar, China, Thailand, Laos, Cambodia,
Vietnam and Malaysia. Four in Thailand.
1. Middletonia evrardii (Pellegr.) C.Puglisi, Taxon. 65: 286. 2016
Distribution.— Lao PDR, Vietnam.
Thailand.— EASTERN: Nakhon Ratchasima, CENTRAL: Nakhon Nayok
Ecology.— Evergreen forest.
Note.— The material from Thailand differs
slightly from the Vietnamese material, especially in
the leaf shape which is more elongated and with an
acute apex in the Thai specimens. As there are rather
few specimens from throughout the distribution
range, with no floral material from Thailand available
for dissection, further collections are necessary
to assess whether the Thai and Vietnamese plants
belong to one or more species.
2. Middletonia glebosa C.Puglisi, sp. nov.
Similar to Middletonia regularis in having the inflorescences shorter than the leaves and to Middletonia reticulata in the shortly caulescent habit. Differs from both in having a dense indumentum on the adaxial side of the leaf, with glands and eglandular hispid hairs (upperleafsurface glabrescent or minutely glandular in Middletonia regularis, glabrescent in M. reticulata), and in the short, non-twisted, lumpy and irregular fruit (longer, weakly to strongly twisted, smooth and regular in M. regularis and M. reticulata).
Type: Thailand, Sukhothai, Ram Kham Haeng National Park, Khao Luang, alt. 520 m, 11 Oct. 2012, fr., Middleton, Karaket, Suddee & Triboun 5559 (holotype E [E00547434]; isotypes BK, BKF [SN201922]).
Distribution.— Cambodia.
Thailand.— NORTHERN: Sukhothai.
Ecology.— Mixed deciduous forest with
bamboo on granite bedrock.
Etymology.— The specific epithet is the Latin
adjective glebosus, -a, -um, which means “lumpy”
and refers to the peculiar surface of the capsule.
Notes.— In Ram Kham Haeng National Park
this species grows in a mixed population with
Middletonia reticulata. The two are readily told apart
in the field by Middletonia glebosa having softer,
paler leaves, a shorter inflorescence, generally
slightly smaller flowers, and the curious short,
straight, lumpy fruit. The species is known only from
Ram Kham Haeng National Park and a single collection
made around 150 years ago in Cambodia.
The Cambodian collection, placed in Paraboea
regularis by Xu et al. (2008), is only in fruit so the
identification will need to be verified with flowering
material. However, the fruit of this species is rather
distinctive.
3. Middletonia regularis (Ridl.) C.Puglisi, Taxon. 65: 287. 2016.
Distribution.— Malaysia.
Thailand.— PENINSULA: Surat Thani, Phangnga;
SOUTH-WESTERN: Kanchanaburi.
Ecology.— Lowland evergreen forest on
limestone soils.
Note.— The protologue of Paraboea monticola
suggests the flowers to be much larger: “lobes …
6–9 × c. 6.5 mm”. However, none of the material
available for this study had lobes longer than 3.3 mm.
4. Middletonia reticulata (Barnett) C.Puglisi, comb. nov.
— Boea reticulata Barnett, Nat. Hist. Bull.
Siam Soc. 20: 20. 1961.
Type: Thailand, Chiang
Mai, Mae Wang
Ecology.— Mixed deciduous forest on granite
bedrock.
Distribution.— Currently endemic to Thailand
but possibly also occurring in Lao PDR and Myanmar.
Thailand.— NORTHERN: Mae Hong Son; Chiang Mai; Lamphun; Lampang; Phrae; Sukhothai.
Note.— This species is resurrected from synonymy
of Middletonia multiflora (R.Br.) C.Puglisi
from which it differs in the distinctively reticulate
venation pattern covered in loose brown indumentum
on the lower surface of the leaves, and in the auriculate
leaf base. Middletonia multiflora has a denser indumentum
on the leaf and the tertiary venation is less
densely reticulate and less visible altogether.
Middletonia multiflora is widespread along the
northern distribution of the genus (from India to
Vietnam), but none of the material from Thailand
studied can be attributed to M. multiflora.
Carmen Puglisi and David J. Middleton. 2017. A Revision of Middletonia (Gesneriaceae) in Thailand. THAI FOREST BULL., BOT. 45(1); 35–41. DOI: 10.20531/tfb.2017.45.1.07