| A karyomorphological study on the genus Eremopyrum By Priyabrata SARKAR Department of Botany, University of Manitoba, Winnipeg, Canada At present most classifications of the Gramineae divide the family into tribes, genera, and species on the basis of the structure and arrangement of the spikelets. However, it appears that morphological studies alone cannot provide all the data necessary for the ideal natural classification aimed at in scientific taxonomy. On the basis of the studies on the morphology of chromosomes and their basic numbers, AVDULOV (1931) attempted to subdivide the grasses from a phylogenetic point of view. Cytological methods were found to be helpful as a tool, but have been put to little use except in the genera Aegilops (SENJANINOVA-KORCZAGINA 1932) and Triticum (KAGAWA 1929; BHATIA 1938; LEVITSKY et al. 1939; PATHAK 1940; CAMARA 1943; SCHRIMPF 1951 and others). The evolutionary development of Triticum can now be partially traced using the method of genome analysis (MCFADDEN and SEARS 1946). However, the origin of the B-genome is still unknown and the search for it indicates a need for a better understanding of the wheatgrasses which are in taxonomical disorder. In the present study only one group of species of wheatgrasses will be discussed. As early as 1829 LEDEBOUR placed Agropyron cristatum and A. triticeum in a new section Eremopyrum. Later JAUBERT and SPACH (1850-53) gave Eremopyrum a generic status and included in it the annual species orientale and squarrosum. The recognition of Eremopyrum as a separate genus was helpful in making it possible for others to put the annual wheatgrasses in one separate group. In recent years the Russian taxonomist NEVSKI (1936) has attempted to clarify the position of the wheatgrasses and their relatives. According to his classification, the content of the genus Agropyron in its wider sense has been separated under three more genera, viz., Roegneria, Elytrigia, and Eremopyrum. He places the genus Eremopyrum in the subtribe Aegilopinae along with Triticum, Secale, Aegilops, Haynaldia, and other annuals. |
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