The President's Address. By Dulcinfield H. Scott. 13T 



ference in the presence of numerous lateral fructifications. In 

 anatomical structure, the American species so far investigated agree 

 wonderfully closely with the European species of Benncttites, but it 

 must be remembered that the vast extent of the material will 

 necessitate many years of arduous research before its investigation 

 can be completed. During the eight years or so that Dr. Wieland 

 has been at work, a marvellous amount has been accomplished. 

 His results are embodied in a magnificent volume issued last August 

 by the Carnegie Institution of Washington.* I will now go on at 

 once to give a brief account of Dr. Wieland's discoveries eluci- 

 dating the structure of the Bennettitean flower. 



The male organs of the Bennettitese were first found in 1899,, 

 in the species Cycadeoidea inyens.'\ Two years later the important 

 fact was established that the organs of both sexes occurred in the 

 same fructification, the whole thus constituting a ' hermaphrodite," 

 or bisexual flower.l This discovery, though now of six years' 

 standing, scarcely attracted the attention it deserved, until the 

 publication of the full details within the last few months. 

 Twenty-five trunks bearing bisexual flowers have now been inves- 

 tigated, belonging to seven American species. The conditions in 

 Cycadeoidea dacotensis, one of the cases most fully investigated, 

 are as follows. The whole fructification has a length of about 

 12 cm., and protrudes beyond the leaf-bases of the trunk. About 

 half the length is occupied by the peduncle, the upper part of 

 which bears 100 or more spirally arranged bracts, inclosing the 

 essential organs. The centre is occupied by the ovuliferous cone, 

 about 4 cm. in height, corresponding to the receptacle, with its 

 seeds and other appendages, as shown in the diagram of Bennettites 

 Gibsonianus, (plate VII. fig. 2, A). In C. dacotensis, however, the 

 form of the central cone is much more pointed, and the stage of 

 development far earlier, immature ovules taking the place of the ripe 

 seeds of the more advanced European specimens (plate YIII. fig. 4). 



* American Fossil Cycads. By G. R. Wieland, 1906. 



t A Study of some American Fossil Cycads. Part I. The Male Flower of 

 Cycadeoidea. Amer. Journ. Science, vii., 1899. 



X Op. cit., Part IV. On the Microsporaugiate Fructification of Cycadeoidea. 

 Amer. Journ. Science, xi., 1901. 



EXPLANATION OF PLATE IX. 



Fig. 5. Cycadeoidea ingens. Restoration of an expanded bisexual flower in 

 longitudinal section, showing the central ovuliferous cone, the com- 

 pound stamens bearing numerous synangia, and the surrounding 

 bracts, hairy with ramenta. About half natural size. From Wieland's 

 "American Fossil Cycads." 

 ,, 6. Cycadeoidea ingens. Plan of the bisexual flower, consisting of a central 

 ovuliferous cone, an hypogj'nous whorl of compound stamens, united 

 at the base, and a series of spirally inserted enveloping bracts, all 

 shown diagrammatically on about the same scale as fig. 5, and as if 

 pressed out flat. From Wieland's " American Fossil Cycads." 



