﻿142 REPRODUCTIVE STRUCTURES. 



object was one of great beauty, and it was at once evident that the essential 

 organs and structure of staminate fructification in the Cycadeoidea? had at last been 

 discovered. 



The results of the writer's earlier study of this flower were published in the 

 American Journal of Science for March, 1899 (187). But that it was bisporangiate 

 was not at once appreciated, although in a small area on the border of the crystal- 

 lined cavity just mentioned a palisade-like structure of light-colored and chalcedon- 

 ized material was noted, and at first regarded as an accident of silicificatiou. Had 

 we fully known how to interpret the evidence this would have been recognized 

 as a portion of the apical ovulate strobilus which had originally occupied approxi- 

 mately the position of the druse-lined central cavity. The synangia-bearing axis 

 was, however, correctly regarded as a disk composed of a series of fused fronds with 

 their fertile pinnules turned inward, and the distribution of the synangia was 

 described. Also their Marattiaceous structure was pointed out, as well as the 

 exceedingly clear additional evidence which this unique type of fructification 

 offered in favor of the current belief in the direct descent of the cycads from such 

 tree ferns as the Marattiacefe. 



In conclusion, the writer said: 



" It has probably been the opinion of all botanists, since it was discovered that 

 Slangeria paradoxa is a cycad, and not a tree fern as originally described, that the 

 relationship between the ferns and cycads must be an exceedingly close one. All 

 later investigations have tended to strengthen this belief, and Scott has recently stated 

 that the evidence in favor of filicinean ancestry of the Cycadese must now be considered 

 ' overwhelming.' It was scarcely to be expected, however, that forms bearing strong 

 testimony on this point should display such a marked combination of advanced as well 

 as ancestral characters." 



The next important step, the discovery of the bisporangiate character of male 

 fructification and the strong possibility of bisexuality in some of the Cycadeoideas, 

 was made by the writer as soon as study was directed to the Minnekahta specimens, 

 of which many were added to the Yale collection early in 1899. These new obser- 

 vations, first made in the previous year, were briefly announced in the Yale Scientific 

 Monthly for March, 1900, at which time a somewhat extended examination of bispo- 

 rangiate axes had already been made, but were not more fully discussed until June 

 of the following year, when the subject was again resumed in the writer's paper on 

 the microsporangiate fructification of Cycadeoidea (192). In this contribution a 

 general statement of the results of the writer's study of fructification in Cycadeoidea 

 was given. The bisporangiate strobilus of Cycadeoidea dacotensis was described, 

 and the earliest statements as to disk organization and the Marattiacean structure of 

 the sori or synangia fully verified, it being proved that, barring the fact of their 

 pollen-bearing function, there was a closer agreement with the synangia of Marattia 

 than with those of any other known genus, living or extinct. The true nature of 

 U'illiamsonia was indicated, it being made wholly clear that the "disks" from the 

 Yorkshire coast, described by Williamson, must mostly be not "carpellary," but 

 staminate, and identical in all essential characters with the staminate disks of the 

 bisporangiate strobili from the Black Hills. Furthermore, it was pointed out that 



