Wednesday, March 31, 2021

[Botany • 2021] Ceropegia calcicola & C. thorutii (Asclepiodoideae, Apocynaceae) • Two New Species of Ceropegia on Limestone Hills in Northern Thailand


Ceropegia calcicola Kidyoo

in Kidyoo, 2021.
Tropical Natural History. 21(1)

Abstract
Two new lithophytic climbers with clustered fusiform roots, Ceropegia calcicola Kidyoo and C. thorutii Kidyoo, from northern Thailand are here described. Illustrations, photographs, and comparisons of diagnostic characters with the morphologically similar species are provided.

 Keywords: Ceropegia calcicola, C. thorutii, section Chionopegia, section Janthina, twining herb

Ceropegia calcicola Kidyoo.
A. Flowering branch. B. Acluster of fusiform roots. C. Open flower. D. Flower bud. E. Bottom view of flower showing calyx. F. Longitudinal section of flower showing corona and gynostegium. G. Side view of gynostegium and corona. H. Top view of gynostegium and corona. I. Pollinarium. J. Fruit.
Photos by Manit Kidyoo from M.Kidyoo 1561 (A-I) and M.Kidyoo 1640(J)


Ceropegia calcicola Kidyoo sp. nov.

Ceropegia calcicola differs from the morphologically similar C. khasiana in having ovate leaves, entirely glabrous corolla and shallowly bifid interstaminal corona lobes. In contrast, C. khasiana has lanceolate or linear-lanceolate leaves, corolla tube with a ring of trichomes on the inside at the distal part of the swollen basal portion, corolla lobes that are puberulent on the adaxial surface, and deeply bifid interstaminal corona lobes. 

 Etymology.– The specific epithet ‘calcicola’ refers to limestone hill, the usual habitat of this plant.

Ecology and distribution.– Ceropegia calcicola is endemic to Thailand, occurring on limestone rock in shady to open areas on limestone hills at 350–1600 m alt. It usually grows inside rock cracks or rock pools where humus soil has collected. Its branches climb up small shrubs or cliffs. Flowering occurs from July to October.


Ceropegia thorutii Kidyoo sp. nov. 

 Ceropegia thorutii is similar to C. elegans in having pedunculate cyme, strongly curved corolla tube being inflated at base, broadly ovate-triangular corolla lobes shorter than corolla tube and joined at tips forming a subglobose dome, but can be distinguished by its glabrous corolla tube being slightly inflated at base, bifid interstaminal corona lobes with triangular segments being shorter than half the length of the staminal corona lobes, and spathulate-clavate staminal corona lobes. 

 Ecology and distribution.– Ceropegia thorutii is endemic to Thailand, occurring on limestone rock in shady areas within highland limestone forest at 1,500–1,600 m alt. It grows inside rock cracks or rock pools where humus soil has collected or in calcareous soil intermingled with other herbs and small shrubs. Its stem and branches usually climb up on small shrubs and cliffs, or branches can be pendent. Flowering occurs in July–October.

Etymology.–The specific epithet, ‘thorutii’ was designated in honor of Mr. Chanin Thorut who first discovered and drew my attention to this plant.


Manit Kidyoo. 2021. Two New Species of Ceropegia (Apocynaceae, Asclepiadoideae) on Limestone Hills in Northern Thailand. Tropical Natural History. 21(1); 1-11. tci-thaijo.org/index.php/TNH/article/view/245810