Revisions of Some Plant Phyla 33 



cies of Ginkgo, a large Chinese and Japanese tree, but in the 

 Tertiary there were many species of this genus, and of other now 

 wholly extinct genera. (Pf. II, i, 108.) 



Order Gnetales. The Joint-Firs. Chlorophyll-green terres- 

 trial plants, shrubby in size and structure, with a branched or 

 simple stem, undivided leaves, monoecious sporophylls, non-motile 

 sperms and naked seeds. They are related to the Cycads, and 

 possibly should be included in this phylum. 1 here are three genera 

 of doubtful mutual relationship. They are usually referred to a 

 common family, Gnetaceae, with no good reason. They probably 

 represent the remnants of as many divergent families. 



Family 11. Ephedraceae. Small, Equisetum-like evergreen 

 shrubs with reduced, opposite leaves. Ephedra. (Species 35.) 

 (Pf. II, I, 117.) 



Family 12. Gnetaceae. Shrubs and trees with large, opposite, 

 evergreen, pinnately-veined leaves. Gnctuni. (Species 15.) (Pf. 

 II, I, 120.) 



Family 13. Tumboaceae. Short, thick-stemmed woody plants 

 with two large, opposite, parallel-veined leaves. Tiimboa {Wel- 

 zi'itschia). .(Species i.) (Pf. II, i, 123.) 



Phylum XIV. ANTHOPHYTA. The Flowering Plants. 



Typically chlorophyll-green plants (a few colorless hystero- 

 phytes), ranging from small or even minute plants to great trees 

 a hundred or more meters in height ; alternation of generations 

 obscured by the extreme reduction of the gametophyte to a con- 

 dition of dependence upon the long-lived, leafy-stemmed sporo- 

 phyte. Spores of two kinds (heterosporous), produced on sporo- 

 phylls which are borne in modified, often much reduced strobili 

 (flowers) ; microsporophylls (stamens) normally with two spo- 

 rangia (pollen sacs) ; the microspores being set free (as "pollen ") 

 when mature ; megasporophylls (carpels) folded lengthwise (con- 

 stituting the "pistil"), enclosing the sporangia (ovules) in which 

 the megaspores remain and develop the minute gametophyte ; 

 archegones very much reduced, including little more than the tgg, 



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