Monday, December 12, 2011

[Botany • 2010] 2 new Petrocosmea | ม่วงสอดสี P. bicolor | ม่วงกำมะหยี่ P. pubescens • from Karst Limestone, northern Thailand



ABSTRACT
Two new species of Petrocosmea section Deinanthera are described, P. pubescens D.J.Middleton & Triboun and P. bicolor D.J.Middleton & Triboun.


ม่วงสอดสี
Petrocosmea bicolor
D.J.Middleton & Triboun, sp. nov.
A Petrocosmea grandifolia et Petrocosmea heterophylla corollis bicoloribus et bulbillis in multis foliis adsunt distincta. Typus: Thailand, Chiang Mai, Fang District, Doi Ang Khang, vertical limestone cliff face in montane forest, 21 Sept. 2008, Middleton, Karaket, Triboun, Kawatkull & Meeboonya 4543 (holotype BKF; isotypes A, BK, E). Figs. 1, 3A–C.

Distribution.— Only known from Doi Ang Khang in Chiang Mai, Thailand.
Ecology.— In montane moist seasonal forest on karst shady limestone at ca 1,450 m in altitude. Flowering and fruiting periods unknown.

Notes.— This is the only species in Petrocosmea sect. Deinanthera with a strongly bicolourous corolla with the upper lip much paler than the lower. It is otherwise rather similar to Petrocosmea heterophylla and P. grandifolia, both of which have larger white fl owers. We have also not found any evidence that bulbils have previously been recorded in the genus.



ม่วงกำมะหยี่
Petrocosmea pubescens
D.J.Middleton & Triboun, sp. nov.
Ab aliis speciebus Petrocosmeae sect. Deinantherae combinatione foliorum peltatorum, pilorum longorum villosorum et corollarum purpurearum differt. Typus: Thailand, Chiang Rai, Mae Fa Luang District, Doi Tung, montane deciduous forest on karst limestone, 23 Sept. 2008, Middleton, Karaket, Triboun, Kawatkul & Meeboonya 4553 (holotype BKF; isotypes BK, E). Figs. 2, 3D–E.

Distribution.— Only known from Doi Tung in Chiang Rai, Thailand.
Ecology.— In montane deciduous forest on karst limestone at 1350–1400 m in altitude.
Flowering and fruiting periods unknown.

Notes.— This is perhaps the most distinctive species of Petrocosmea sect. Deinanthera due to the peltate leaves and deep purple corollas. No other species in Petrocosmea sect. Deinanthera have peltate leaves and only Petrocosmea bicolor has such deep purple corollas, albeit not uniformly in that species.


Middleton, D.J. & Triboun, P. 2010. Two new species of Petrocosmea (Gesneriaceae) from Thailand. Thai For. Bull. (Bot.) 38: 42–47.: http://web3.dnp.go.th/botany/PDF/TFB/TFB38/06_Petrocosmea.pdf