J Integr Plant Biol. ›› 1960, Vol. 9 ›› Issue (1): -.

• Research Articles •    

A Study on the Tribe Eragrostideae and Its Two Genera New to China

P. C. Keng and L. Liou   

Abstract: Besides introduction, six sections are incorporated in this paper. In the first two sections, the two genera, Eragrostiella and Sclerodactylon each with a single species distributed in Yunnan and new to China, are described, and their type species, Eragrostiella leioptera and Sclerodactylon juncifolium, are designated respectively. Among the two species discovered in Yunnan province, the first is Eragrostiella lolioides (Hand.-Mazz.) Kong f., a new combination made from Eragrostis lolioides Hand.-Mazz. (Symb. Sin. 7: 1282-1283, 1936), while the second, Sclerodactylon micrandrum Keng & Liou, a low perennial grass, is a species new to science. Both of them are described and illustrated, and a Latin description for the new species is appended. The type specimen of this new species is deposited in the herbarium of Sun Yatsen Memorial Botanical Garden, Nanking, China. In the first section there is also another new combination, Eragrostiella coromandelina (Koenig) Keng f. & Liou, made from Poa coromandelina Koenig (ex Rottl., Ges. Naturf. Fr. Neue Schrift. 4: 191, 1803), an Indian species from the Coromandel coast. In the second section, an interrupted distribution of the two species of Sclerodactylon, one in Eastern Madagascar and the other in SW. China, is mentioned. Other genera of Grasses and the families of dicots having similar distributions, such as Harpachne, Thuarea, etc., are also stated here. The third section of this paper deals with the relationships and derivations of the two above mentioned genera. It is shown that both Eragrostiella and Sclerodactylon are related to Eragrostis and probably derived from it. The genus Sclerodactylon, however, also indicates some characteristics intermediate between Eleusine and Dactyloctenium. The fourth section gives chronologically a brief historical sketch on the study of the natural group Eragrostideae. The sketch shows that the taxon o this group becomes higher and higher in rank, since it was at first treated as a subtribe under Festuceae, then a tribe, a series, and at length as a subfamily in itself. As to the origin of the tribe, the authors of this paper consider that the character of spikelet-morphology is much more important in the natural system than that of leaf-anatomy, and they recognize the tribe Eragrostideae being intermediate between Festuceae and Chlorideae. Therefore, they do not agree with the opinion that the two tribes, Eragrostideae and Paniceae, were originated from one common stock. The subfamily Agrostidoideae proposed in 1951 in opposition to Bambusoideae is also published herewith in Latin. In the fifth section of this paper, the various genera of the tribe Eragrostideae of China are discussed. There are in China, 12 genera ascribed to this tribe and divided into three subtribes. Among these subtribes, the first Eragrostidinae contains 5 genera: Eragrostis, Harpachne, Desmos-tachya, Sclerodactylon, and Eragrostiella; the second and the third subtribes, Tridentinae and Eleusininae, are proposed here as new ones; the former contains 5 genera: Orinus, Cleistogenes, Diplachne, Leptochloa, and Tripogon; the latter includes only Eleusine and Dactyloctenium. A phylogenetic diagram showing the relationships and possible lines of the evolution of these Chinese genera and two American ones, Tridens and Triplasis, is given at the end of this section. Finally in the sixth section, there is a key to the three subtribes and the 12 genera attached below the description of the tribe. Then the 12 genera are listed under the three subtribal descriptions in their proper places. A Latin description is also given to each of the two new subtribes, Tridentinae and Eleusininae. The seven new species and one new variety of this tribe, which are published only in Chinese in the “Flora Illustralis Plantarum Primarum Sinicarum Gramineae, 1959”, are supplemented here with Latin descriptions. They are as follows: 1. Eragrostis perlaxa Keng, 2. E. ferruginea var. yunnanensis Keng, 3. Orinus anomala Keng, 4. Cleistogenes polyphylla Keng, 5. C. longifiora Keng, 6. C. gracilis Keng, 7. C. mucronata Keng, and 8. Tripogon nanus Keng.

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