A monograph of the Genus Aristida

We find the interpretation of the genus Aristida by BEAUVOIS in his work Essai d’une nouvelle Agrostographie on pag. 33. Aristida lanata is the only species mentioned by him and the genus is figured on Pl. VIII. fig. X. This figure is a rather rough sketch and represents Aristida ciliata DESF.. In the figures b and c there is a well-developed column and the central awn is plumose, the articulation between lemma and column is omitted or overlooked. Aristida lanata, as mentioned by BEAUVOIS, is quite different from the A. lanata, described by FORSKÅL, where all the awns are plumose and the glumes are quite different. BEAUVOIS tells us that among all the Aristidas he has found in herbaria, this one is the only species where the central awn differs in structure from the lateral ones, the central awn being a true awn (arista) and the lateral ones „setae” only. The genus with these characters he accepted as the genuine Aristida and hence described the genus with the 3 awns of equal structure as new under the name of Chaetaria. This interpretation of LINNÉ’S genus Aristida was however wrong. LINNNAEUS based the genus on the Aristida adscensionis, the only species mentioned in the description in the year 1753. Both genera Aristida and Chaetaria are quite identic. Among the 25 species enumerated by BEAUVOIS under Chaetaria, we find 4 species with a? and 2 species, A. capensis and A. vestita, do not belong to the genus Chaetaria (BEAUVOIS could not study them or he overlooked the articulation of the column). Aristida capensis has plumose awns and belongs to the section Stipagrostis and A. vestita belongs to the section Arthratherum. BEAUVOIS figures two species of his genus Chaetaria (Plate VII. fig. V. and VI.). The first figure is Aristida stricta MICHX., the second is Chaetaria capillaris, the name is a misprint for C. capillacea based on Aristida capillacea of LAMARK. TRINIUS accepted in the year 1824 the genus of BEAUVOIS as a section of the genus Aristida in his Dissertatio botanica De Graminibus Unifloris et Sesquifloris on p. 175 with the diagnosis: „Perianthium cum setis non articulatum”. This section is also accepted in this work, it contains about 200 species, North America and Mexico have about 47 species, Central and South America have about 58 species. The West Indian Islands are comparatively rich in species, about 15. In the Old World we find but one species in Europe, the continent of Africa has about 38 species, Madagascar and the adjacent islands have 7 representatives. There are known 2 species from Nova Caledonia and 29 species on the continent of Australia. Asia has about 10 species.