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queetiOD, with the abiindaDt and so long enig- matic Cordaites. This nocient plant was for- merly regarde<i as the forerunner of the family of cycads ; but now, in the light of these dis- coveries, it is ahnost universally regarded as coniferous. It was one of the GarlLeet types of land vegetation to appear on the globe, running far back into Devonian, and even into Silurian time. The figures of the accompanying plate,

��NCE, [Vol- V- Ko. I»

remarkable manner the almond-shaped nuts borne by the present maiden-hair tree.

Though these carlxmiferoas plaatii were at first commonly regarded as cyoadaceous, etiU the long, ribbon-like leaves of certain cordaitean forms (Poa-Cordaites of Grand'Eury) led some eminent authors, including the late Professn Goppert, to consider them monocotjledonoin. and the precursors of our lilies, reeds, grasaeC) and ^o of the palma. But even Ui e a c inis-

���rtwolferoDa, Kogluiit. S. Qlnkgnph] SHjniui* iiniaif, iwr^ rhuUc. BafrauUl. i. UlDkgD i?iui[;> (BiDBBn.],U«r:ooUu.Csp«Bah«mui,Bpllibiir(U«burl>) ndlwiliildH. Ungir: Pert Onion b«d>. mIoccQe, Gmmluid. 10. Qlnkgo bllobi. L. ; Uvltig, Wuhlngi

kindly drawn for me by Ensign Everett Hay- den, U. S, navy, have been selected with a view to illustrating the phylogeny of the genus Ginkgo: and they are numbered, and as nearly as practicable arranged upon the plate, in the order of supposed development, Tfom the true Cordaites to the living Ginkgo biloba ; this being also, as will be observed, substantially the ciironological order of their appearance.

The broad leaves of some species of Coidai- tes, though more or less elongated or ellijitical in shape, possess a nervation strikingly similar to that of the later ginkgo-liku forms ; while the familiar ft-uits so abundant in the coal- measures, and which are now known to be those of Cordaites, resemble in an equally

��3. FifgiDonbyUum [NoegaenibU) OBbefUiuin (U«il. • .1, Bapcna: PermUn, H^noTi. 4. Va\tn (Jesiij.nuiU] IIOo- ir: oojIU', Slberin (iMtonil by BmtJ. 6. UlBk|n diBlMW ijatiil*. n.ap.: Lununtv, Pidotof Bocki,WyoniliiaT«rrit(M. VelLownoDe. 9. Ginkgo (Sadibaria) idlaDIolda, tiDMrr
 * . All IbD Itgiin* are reduced onr-b>if. '

��takee have not been without their uses. It if the peculiarity of science that in its very erron knowledge is extended. The theory thiit Cor- daites was cycadnecons was not wholly Tklte ; the suggestion that it might be monoootyledo- nous contained a ' soul of tmth ; ' and the prca- ent opinion that it was coniferous is. I vtntun to assert, not wholly true. The truth liea in the midst of ail these opinions. It seems to be this : there were no true paleozoic CycadaraMt monocotyledons, nor Coniferae ; but Cordaitea was the prototype of ihcm all. It was in the Trias, whose flora is unfortunately tbe leas^ known of all the formations in ]mat time, liiat all these definite types of vegetation were difr ferentinted from this corapreliensive type, — ;- the Cycadaceac through their Macropteryigjurat.

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