420 



SCIENCE 



[J^-. S. Vol. XXVI. Ko. 665 



great grotip of Mesozoic plants, the Bennei- 

 titeae, whicli afford the key to the ancestry 

 of the race in question." They then con- 

 struct a mental picture of a primitive strohilus 

 (flower) consisting of a large, elongated, coni- 

 cal axis, bearing megasporophylls above, and 

 microsporophylls below, and still below these 

 a perianth of usually more than one whorl. 

 Such a primitive flower is conceived to have 

 been polypetalous, hypog-ynous, and apocarp- 

 ous. Structures similar to this imaginary 

 primitive flower occur in Magnoliaceae, 

 Banunculaceae, Nymphaeaceae and Calycan- 

 thaceae among dicotyledons, and in Alis- 

 maceae, Butomaceae and Palmaceae among 

 monocotyledons. 



The authors then take up an examination 

 of the Bennettiteae, which " appear to afford 

 the long sought for clue to the phylogeny of 

 the angiosperms." They show that in these 

 plants the anthostrobilus is sufficiently like 

 that of the simple angiosperms to warrant the 

 suggestion that the latter are derived from 

 structures much like the former. They are 

 able to reconstruct the anthostrobilus of 

 Bennettites, and a comparison of this with the 

 pro-anthostrobilus of the hypothetical Hemi- 

 angiospei-mae, and the primitive flower re- 

 ferred tO' above shows that the steps from the 

 Bennettiteae to the angiosperms are easy and 

 quite probable. In their discussion they make 

 one remark which will surprise many a 

 botanist who has not kept in touch with the 

 recent advances in paleobotany, namely : " the 

 seed itself is an exceedingly ancient organ, 

 dating far beyond the period at which we first 

 became acquainted with fossil plants ; in other 

 words, it was a highly evolved structure at a 

 very remote period in geological time." Yet 

 while all these early seed plants were gymno- 

 spermotis, it does not follow that they gave 

 rise to the sub-class Gymnospermae, as now 

 understood. On the contrary, it is shown to 

 be probable that the gymnospermous Bennet- 

 titeae gave rise rather directly to the Angio- 

 spermae. 



The authors show how entomophily helped 

 shape the developing primitive flower, and re- 

 gard it as an important factor in the evolu- 

 tion of the angiospermous flower. They close 



their paper with a couple of pages of general 

 conclusions and summary, including a helpful 

 geological table of angiospermous relation- 

 ships, and finally a bibliography of seventy-one 

 titles. 



The second paper, by O. F. Cook, " Origin 

 and Evolution of Angiosperms through 

 Apospory," was published in the Proceedings 

 of the Washington Academy of Sciences (vol. 

 9, pp. 159-178, July 31, 1907). In it the au- 

 thor first refers approvingly to the now widely 

 accepted hypothesis as to the origin of gymno- 

 sperms through the ferns and the Cycado- 

 filices, and then remarks that while evidence 

 of such origin of the gymnosperms has in- 

 creased rapidly in recent years, it " has not 

 been accompanied by any equally convincing 

 indications that the angiosperms shared the 

 same pteridophytic ancestry." He, therefore, 

 suggests that " morphologists may be willing 

 to consider an alternative possibility, that the 

 origin of the angiosperms should be sought 

 more directly in some such primitive condi- 

 tion as the thallose liverworts, without the 

 need of following back through the stages of 

 development represented by the ferns and 

 other vascular cryptogams." In brief, his sug- 

 gestion is that " the female reproductive ap- 

 paratus of the angiosperms is analogous to the 

 fern-prothallia which are sometimes produced 

 directly from the parent plant without the 

 intervention of spores, that is, by aposporous 

 growth from cells of the parent fronds." 



The author then develops the theory that 

 angiosperms have descended from an Antho- 

 ceros-like type. He holds that Anthoceros is 

 not representative of ancestral pteridophytes, 

 a contention which appears to us to be quite 

 unnecessary, even from his own standpoint, 

 since it is evident that pteridophytes and 

 angiosperms have much in common. He sug- 

 gests that were the capsule of Anthoceros to 

 become perennial, and " produce prothallia in- 

 stead of spores" the transition to the higher 

 plants would be accomplished. 



The paper is quite markedly philosophical, 

 and while one may not be able to accept its 

 conclusions, every botanist will find it profit- 

 cble reading. 



