20S 



MORPHOLOGY 



Leaves. — The leaf is vcrv cliaracteristic in fnrm and vcnalinn (lig. 

 46s), tlie broadly wedge-shaped outline, often more or less lobed, and 

 the forked veins resembling somewhat the leaves of maidenhair fern 

 and suggesting the common name. The mesophyll has the peculiar 

 character (transversely elongated and very loosely arranged cells) 

 described under Cordaitales and Cj'cadales (p. 193J. 



Figs. 466, 467. — Staminate strobilus of Ginkgo: 466, the clu.stcrs of strobili borne on 

 dwarf brancfics; 467, a single strobilus, showing the character of the individual stamens 

 (a staik ending in a knob and bearing two pendent sporangia). 



Strobili. — The ^trolMli arc monoh])orangiale, and the two kinds of 

 strobili occur on different trees (di(^eciou>). 



Slaminale. — The staminate strobili occur in loose catkindike clusters 

 borne on the d«'arf liranches (fig. 466). The sporophvU (stamen) con- 

 sists of a stalk ending in a knob, from beneath one side of which two 

 (sometimes three to seven) pendent sporangia are borne (fig. 467). This 

 tvpe of stamen suggests the epaulet t\'pe found among Cycadofilicales 

 (see p. 1S4). The de^'elupment uf the sporangium is regularl veusporan- 

 giate, as described under Cycadales (p. 194). 



