 |
Elatostema kaweesakii Triyutth. & L.F.Fu, E. rubricaule Triyutth. & L.F.Fu,E. saxatile Triyutth. & L.F.Fu, in Triyutthachai, Fu, Triboun, Wei & Pornpongrungrueng, 2022. |
Abstract
Three new species of Elatostema (Urticaceae) from Thailand, E. kaweesakii Triyutth. & L.F.Fu, sp. nov., E. rubricaule Triyutth. & L.F.Fu, sp. nov. and E. saxatile Triyutth. & L.F.Fu, sp. nov., are newly described and illustrated. These new species can be distinguished by the presence of rhizome. Elatostema kaweesakii is similar to E. atroviride. Elatostema kaweesakii is a lithophyte growing in limestone crevices. It differs from E. atroviride by its large swollen rhizome, glabrous stem, glabrous receptacle, number of tepal in staminate flower, absence of tepal in pistillate flower, presence of staminodes in pistillate flower and smooth achene. Elatostema rubricaule and E. saxatile are found on sandstone habitats. They have distinct flattened and disk-like rhizome. Elatostema rubricaule is distinguished by its distinct sulcate and reddish stem with flattened and disc-like rhizome and chartaceous leaves with entire margin. Elatostema saxatile resembles E. bulbiferum but differs by its flattened and disc-like rhizome, acute leaf apex, glabrous receptacle in pistillate inflorescences, presence of staminodes in pistillate flower, and its sandstone habitat. Descriptions, distribution, ecological and phenological data are provided.
Keywords: Flora of Thailand, limestone, nettle family, rhizomatous plant, Rosales, sandstone, taxonomy
 |
| Elatostema kaweesakii Triyutth. & L.F.Fu, sp. nov. A habit B staminate inflorescence C staminate flower D pistillate inflorescence E pistillate flower F bracteole G achene (Drawn by N. Triyutthachai). |
 |
| Elatostema kaweesakii Triyutth. & L.F.Fu, sp. nov. A habit and habitat B pistillate inflorescence C staminate inflorescences (Photos A, C by K. Keeratikiat, B by Triyutth). |
Elatostema kaweesakii Triyutth. & L.F.Fu, sp. nov.
Diagnosis: Elatostema kaweesakii is similar to E. atroviride W.T. Wang but differed by its large swollen rhizome, staminate inflorescences with 2–7 cm long peduncle, receptacle rectangular, glabrous, staminate flower with 5 ovate tepals, pistillate inflorescences with 5–10 mm long peduncle, receptacle rectangular, glabrous, pistillate flower without tepals, staminode present and achene smooth (Table 1).
Etymology: This species is named in honor of Mr Kaweesak Keeratikiat, who first discovered the plants.
 |
| Elatostema rubricaule Triyutth. & L.F.Fu, sp. nov. A habit and habitat B pistillate inflorescences C staminate inflorescence (Photos by Triyutth). |
Elatostema rubricaule Triyutth. & L.F.Fu, sp. nov.
Diagnosis: Elatostema rubricaule differs from other Thai Elatostema by its distinct sulcate and reddish stem with flattened and disk-like rhizome and chartaceous leaves with entire margin. It grows on seasonally moist sandstone rock (Table 1).
Etymology: Latin ruber, red, and caulus, stem, alluding to stem color of the new species.
 |
| Elatostema saxatile Triyutth. & L.F.Fu, sp. nov. A habit and habitat B stem and rhizome C pistillate inflorescences D staminate inflorescence (Photos by Triyutth). |
Elatostema saxatile Triyutth. & L.F.Fu, sp. nov.
Diagnosis: Elatostema saxatile is similar to E. bulbiferum Kurz, but differs by its flattened and disk-like rhizome, receptacle of pistillate inflorescences glabrous, staminode in pistillate flower 5, acute leaf apex and its sandstone habitat (Table 1).
Etymology: The specific epithet refers to the habitat of this plant that dwelling on the rock.
Natthawut Triyutthachai, Long-Fei Fu, Pramote Triboun, Yi-Gang Wei and Pimwadee Pornpongrungrueng. 2022. Three New Species of Elatostema (Urticaceae) from Thailand. PhytoKeys. 215: 37-50. DOI: 10.3897/phytokeys.215.94591
