. Heredity and evolution in plants . FIG. 95.—Macrozamia spiralis. Tip of the trunk, showing threelateral cones, inserted in the axils of leaves. Photo from specimen inBrooklyn Botanic Garden. (C/. Fig. 96.) they form about one-third of the recovered vegetation ofthe land. One order, the Hemicycadales (Bennettitalesx),then had a cosmopolitan distribution and seemingly wasas important as the Dicotyledons are now. Over 30 speciesof the petrified stems have been found in the Mesozoic In his paper on the Classification of the Cycadophyta (Am., Jour. : 391-406. June, 1919), Wieland states sim
. Heredity and evolution in plants . FIG. 95.—Macrozamia spiralis. Tip of the trunk, showing threelateral cones, inserted in the axils of leaves. Photo from specimen inBrooklyn Botanic Garden. (C/. Fig. 96.) they form about one-third of the recovered vegetation ofthe land. One order, the Hemicycadales (Bennettitalesx),then had a cosmopolitan distribution and seemingly wasas important as the Dicotyledons are now. Over 30 speciesof the petrified stems have been found in the Mesozoic In his paper on the Classification of the Cycadophyta (Am., Jour. : 391-406. June, 1919), Wieland states simple and good reasonsfor letting the name Bennettitales fall into disuse, and substituting there-fore the term Hemicycadales (half-cycads). 212 HEREDITY AND EVOLUTION IN PLANTS terrains of the United States, the Black Hills of SouthDakota alone yielding a score. The Isle of Portland forms. FIG. 96.—Cycas circinalis. Tip of trunk, showing numerous leaf-stalks, and the large terminal cone. Photo from specimen in BrooklynBotanic Garden. (Cf. Fig. 95.) were called Cycadeoidea by the eelebrated geologist Buck-land. The original nanir of the order was derived from THE EVOLUTION OF PLANTS 213
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