The Spore Pattern in some Species of Cheilanthes

Abstract

A B S T R A C T Of the 32 taxa examined, 13 contained 32 spores in each sporangium and are considered apogamous, 14 were sexual species with 64 spores per sporangium, and 5 had 32 spores in some sporangia and 64 in others. When considered as a whole, the spores ranged in size from 29.9 to 74.88,u. Most species had oval or globose spores but several had tetrahedral spores. The spores of all were radially symmetrical. Almost all of the species possessed a crassimarginate type of laesura and all except C. cooperae and C. viscida had a perispore. The ornamentation of the perispore showed the following patterns: napate, granulate, psilate, lobate, foveate, and echinate. The exine pattern was predominantly psilate but foveate, rugulate, napate, and granulate conditions were observed. Seventeen taxa were found to have some degree of spore abortion. THP, GENUS Cheilanthes contains a large number of species and its relationship to other genera of the cheilanthoid ferns is not at all clear. It was felt that a study of the spore morphology of the North American species would be helpful in the clarification of its status as a genus and in its relationship to related genera. The only previously published papers dealing with spores in the genus Cheilanthes are those of Weaver (1896), McVaugh (1935), Harris (1955), Sladkov (1959, 1962), Nayar (1962, 1963), Tschudy and Tschudy (1965), Whittier (1965), and Hitt and Knobloch (1967). METHODS AND MATERIALS-Sixty-five collections among 32 species are considered in the text. Live plants from various sources were used in all cases. The spore number was obtained by placing a single, mature sporangium in a drop of Hoyer's