NO. 1873. CHARACTERS OF OIGANTOPTERIS— WHITE. 515 



(Cat. No. 34062, U.S.N.M. Photographed in natural size.) 



Fig. 2. — Fragment from the lower part of a leaf showing the nervation which is more 

 characteristically represented in the middle of the enlarged illustration. 



(Cat. No. 34074, U.S.N.M. Figure twice natural size.) 



Fig. 3. — Two young leaves, one bifurcated and gradually narrowed downward, the 

 other abruptly constricted at the base of the lamina and petiolate. On the left is 

 seen the base of a partly grown leaf, while on the right is shown a fragment of a leaf, 

 perhaps fully grown. 



(Cat. No. 34073, U.S.N.M. Photographed in natural size.) 



Plate 47. 

 Gigantopteris americana. 



Fig. 1. — Fragment of a leaf of average size illustrating the dicotyledonous aspect of 

 many of the examples. In portions of the specimen the conditions of maceration 

 have brought the nervation into high relief, as photographically represented. The 

 base of the fragment is probably near the point of bifurcation. 



(Cat. No. 34072, U.S.N.M. Figure in natural size.) 



Fig. 2. — Photographic enlargement, showing the nervation of a leaf slightly larger 

 than that seen in figure 1. On the left is seen the secondary nerve, on the right the 

 sutural nerve. A part of the same specimen is shown in natural size in the nature 

 print in plate 48, figure 2. 



(Cat. No. 34061, U.S.N.M. Photograph, twice the natural size.) 



Fig. 3. — Immature scale detached from a strobilus of the type shown in plate 48, 

 figures 3 and 4. It is probably the polleniferous scale of Gigantopteris americana. 



(Cat. No. 34066, U.S.N.M. Illustrated in natural size.) 



Fig. 4. — The same specimen photographed twice the natural size to show the Gigan- 

 topteris nervation of the immature scale. The inner convex portion corresponds to the 

 polleniferous (?) area of the scales seen in plates 48 and 49. 



Plate 48. 

 Gigantopteris americana. 



Fig. 1.^ — Apex of leaf illustrating the dicotyledonous aspect of the fragments. 



(Cat. No. 34063, U.S.N.M. Figure in natural size.) 



Fig. 2. — Photographic print made from a carbon-paper impression of the surface 

 of a leaf fragment to show the nervation. The nature print serves excellently to illus- 

 trate the aspect of the nervilles and the thin sutural nerves. 



(Cat. No. 34061, U.S.N.M. Figure in natural size.) 



Fig. 3. — Strobilus supposed to comprise the polleniferous disks of the same plant. 

 The specimen is broken slightly obliquely to the axis so that the upper convex sur- 

 faces of the distichous scales or bracts are seen in the upper part of the figure, while 

 the under concave surfaces are shown in the fragments lying beyond the plane of the 

 axis in the lower part of the photograph. The polleniferous (?) sacs are imperfectly 

 seen at a few points on the underside of the bracts. 



(Cat. No. 34077, U.S.N.M. Figure, natural size.) 



Fig. 4. — Similar strobilus, broken longitudinally along the axis. Numerous pol- 

 leniferous (sporiferous?) sacs are shown on the underside of the bracts, the borders of 

 which are bent downward. 



(Cat. No. 34078, U.S.N.M. Figure in natural size.) 



Fig. 5. — Lobe bract, similar to the fertile bracts of the strobilus, showing Giantop- 

 teris nervation. This specimen is comparable to that seen in figure 3 on plate 47. 



(Cat. No. 34075, U.S.N.M. Photograph, natural size.) 



