Cytology of Some W. Himalayan Cyperaceae
Cyperaceae are grass-or rush-like herbs occurring in all latitudes under a wide range of physical and physiological conditions. Representatives of this family are readily distinguished from grasses by the mostly 3-ranked leaves, terete or 3-angled solid cuims and by their closed rather than split leaf-sheaths. Willis (1966) estimated about 90 genera embracing about 4,000 species. Hutchinson (1959) considered Cyperaceae to have developed parellel with the grasses through the juncaceous stock
... uncaceous stock from the Liliales. He placed Cyperaceae and Gramineae under two separate orders Cyperales and Graminales and considered the latter to be more highly advanced. Engler and Prantl (1889-1897) grouped Cyperaceae and Graminaceae under Glumi florae, and Juncaceae alongwith Liliaceae under the Liliflorae. However, Snell and Blaser (vide Lawrence 1965) on certain morphological grounds disapproved of any close relationship between the two families Cyperaceae and Gramineae. Ziegen speck (cf. Bor 1960) opined that two lines emerged from the common parental stock, one of which gave rise to Commelinaceae and Gramineae and the other to Juncaceae and Cyperaceae. A lot of controversy also exists regarding the delimitation and evolution of taxa within the family. Hooker (1894) divided the family into four main sections starting with Cypereae and followed by Hypolytreae, Sclerieae and Cariceae. He further split the first section into three tribes Eucypereae, Scirpeae and Rhynchosporeae on the basis of hypogynous bristles and glume characteristics. Hutchinson (1959) divided the family into seven tribes and considered Rhyncho sporeae to be the most primitive followed by Scirpeae, Cypereae, Hypolytreae, Sclerieae, Cryptangieae and Cariceae. In the classification followed by Engler and Prantl (1. c.) the subfamily Scirpoideae has been regarded as the most primitive, followed by Rhynchosporoideae and Caricoideae. Some authors have even gone to the extent of splitting the family Cyperaceae into three independent families i.e. Cyperaceae (restricted to the subfamily Scirpoideae), Rhynchosporeaceae and Cari caceae (vide Lawrence 1965). In view of these diverse opinions it was, thought worthwhile to collect cytological data to see if it could be helpful in resolving some of these issues and also to follow the course of cytological evolution and the mechanism of speciation in this highly fascinating group of plants. In pursuance of this objec tive, investigations were undertaken on 42 taxa of the W. Himalayan Cyperaceae which have hitherto remained unexplored to a large extent.