 |
| Whittieria hengduanensis Z.L.Liang & Li Bing Zhang, in Liang et Zhang. 2024. |
Abstract
A new fern species, Whittieria hengduanensis (Ophioglossaceae), from Sichuan, Xizang, and Yunnan, Southwest China (eastern Himalaya), is described and illustrated. This species is similar to W. engelmannii in the Americas in having a cylindrical rhizome and complex-reticulate venation. In addition, both species grow in open habitat on basic soil. However, the two species are distinguishable in root number per rhizome and the number of the larger areolae per trophophore. Our molecular study also supports that they are sister to each other but divergent at the molecular level. The discovery of W. hengduanensis shows that the genus is intercontinentally disjunct between the Himalaya and the Americas, a unique pattern not having been documented in the literature.
Key words: Adder’s tongues, fern biogeography, intercontinental disjunctions
 |
| Whittieria hengduanensis A, B habitat C lower portion of plant showing stem and roots D individuals in different sizes E trophophores and sporophore stalks F sporophore G veins showing complex-reticulate venation. |
 |
| Whittieria hengduanensis A, B habit C trophophore and base of sporophore D sporophore spike E veins showing complex-reticulate venation. |
Whittieria hengduanensis Z.L.Liang & Li Bing Zhang, sp. nov.
Diagnosis: Whittieria hengduanensis is similar to W. engelmannii but the former has up to 25 (–50) roots per rhizome and 10–20 large areolae per trophophore, whereas the latter has fewer than 15 roots per rhizome and 0–8 areolae per trophophore.
Etymology: The species epithet henduanensis is based on the distribution of this species in the Hengduan Mountain.
Zhen-Long Liang, Li-Bing Zhang. 2024. Discovery of Whittieria hengduanensis sp. nov. (Ophioglossaceae) from Southwest China demonstrates a unique intercontinental disjunct pattern in plants between the Himalaya and the Americas. PhytoKeys 249: 27-36. DOI: doi.org/10.3897/phytokeys.249.135379
