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The present study is based on all the Indian specimens of Ptilophyllum Morris described since 1840 and new specimens collected during the last 20 years. The different species have been grouped under the headings "Impressions", "Incrustations" and "Petrifactions ". Under impressions four species, viz. P. acutifolium Morris (1840), P. cutchense Morris (1840), P. rarinervis (Feistmantel) n. comb. and P. tenerrimum Feistmantel (1877) have been included. All these four species are based on external characters alone. Eight species based on cuticular structure have been described under incrustations. These are P. oldhamii Jacob & Jacob (1954), P. indicum Jacob & Jacob (1954), P. honidum Roy (1963), P. sakrigaliensis Sah (1958), P. distans (Feistmantel) Jacob & Jacob (1954), P. institacallum Bose (1959), P. jabalpurense Jacob & Jacob (1954) and P. gladiatum Bose & Sukh Dev (1958). The remaining species, i.e. P. amarjolense Bose (1953), P. sahnii Gupta & Sharma (1968) and P. nipanica Vishnu-Mittre (1957) are preserved in the form of petrifactions. In these three species, besides the surface characters, the anatomy of the fronds has been studied in detail.
Bose et al. (Thu,) studied this question.
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