Thursday, November 15, 2018

[Botany • 2018] The True Tectaria chinensis (Tectariaceae): Morphology, Distribution, and Allied Species


Tectaria chinensis (Ching & Chu H. Wang) Christenh.
in Dong, Tan, Pham & Phan, 2018. 

Abstract
Tectaria chinensis is a poorly known species from China, with its type being the sole authentic voucher to date. Recent field observations and morphological comparisons reveal its type being an incomplete frond, which resulted in the constant misinterpretation of some morphological characters and the allied species to T. chinensis. In fact, T. chinensis is a very special species restricted in southern China and northern Vietnam and featured by the unique long and erect caudex and the rare combination of partly free venation and vein-dorsal sori. Phylogenetically, T. chinensis was revealed by our previous analyses of five plastid regions to be in the Ctenitopsis group (Clade III or T. subg. Ctenitopsis), forming a sister clade to the lineage of T. fuscipes. A detailed description, explanatory illustrations, as well as distribution and habitat information of T. chinensis are provided.

Keywords: China, morphology, taxonomy, Tectaria, Vietnam, Pteridophytes

FIGURE 2. Tectaria chinensis (Ching & Chu H. Wang) Christenh. 
A & B, habit. C, two long, erect caudices. D, scales on lower stipe. E, part of fragment on upper lamina, showing veins forming costal areoles and sori on anastomosing veins or dorsal on free veins.
 (A from Dong 4343 at IBSC, B–E from Dong 4789 at IBSC).


Tectaria chinensis (Ching & Chu H. Wang) Christenhusz (2010: 58). 
Basionym:— Ctenitopsis chinensis Ching & Chu H. Wang (1981: 124). 
Type:— CHINA. Yunnan: Hekou, in 1955, elev. 100 m, Department of Biology, Yunnan University (DBYU) 512 (holotype PE!)
....

Distribution:—Restricted to southern China and northern Vietnam. In China: southern Yunnan (Hekou, Jinping, Lüchun, Mengla, and Xichou); in Vietnam: Ha Giang (Cao Bo, Vi Xuyen Distr.), Lao Cai (Nam Xe, Van Ban Distr.). This is the first time to confirm T. chinensis in Vietnam. It is also highly expected to find this species in northern Laos.

Note:— The type of Tectaria chinensis, DBYU 512 (PE), is actually an incomplete frond that consists of a broken stipe and a lamina without basal pinnae (Fig. 1). The lowest pinnae seen on the sheet of type specimen was mistakenly regarded as the basal pinnae by Ching & Wang (1981), which leaded them and later authors (Wang 1999, Cheng 2005, Xing et al. 2013) to associate this species with Ctenitopsis subsageniacea sensu Ching (1938: 311) [= T. austrosinensis (Christ 1907: 145) C. Christensen (1934: 177) (Dong 2017)], a species with the basal basiscopic lobes reduced on basal pinnae. Based on the misinterpretation of T. chinensis, we had never associated our new collections featured by long-erect caudices with T. chinensis because in the new collections the basal basiscopic pinnules of basal pinnae are constantly produced (Fig. 2). On the other hand, of all known species in Tectaria from China T. chinensis is the only dubious species which is poorly presented in herbarium; this fact reminded us to connect our new collections featured by remarkable long caudex with T. chinensis. The overall similarity, especially the consistent venation and sori positions between the new collections and the type of T. chinensis makes it sure that our new collections are just the individuals of T. chinensis. Now it is clear that T. chinensis is with the basal basiscopic pinnules being produced on basal pinnae and is not at all similar to T. austrosinensis.
....


Shi-Yong Dong, Shi-Shi Tan, Van The Pham and Ke Loc Phan. 2018. The True Tectaria chinensis (Tectariaceae): Morphology, Distribution, and Allied Species. Phytotaxa. 376(1); 60–67.  DOI: 10.11646/phytotaxa.376.1.6