THE 



AMERICAN JOURNAL OF SCIENCE 



[FOURTH SERIES.] 



Art. X. — A Study of Some American Fossil Cycads. — Part 

 VI* On the Smaller Flower- Buds of Cyeadeoidea ; by 



G. R. WlELANP. 



[Preliminary Notes published by permission of the Carnegie Institution 

 of Washington.] 



In continuing the studies of silicified cycads begun in 1898 

 one of the most pleasing results obtained has been the discovery 

 that some of the large and fine trunks at first thought to bear 

 rather young fructifications are full grown plants, their flower- 

 buds being in reality of quite mature pygmic type. 



Of these trunks, which evidently fall into several distinct 

 specific series, the one to which most study has been devoted 

 is No. 3 of the Yale collections. Originally referred by num- 

 ber only together with various other Yale cycads and one IT. S. 

 National Museum specimen to Cyeadeoidea dacotensis^ this 

 handsome columnar trunk or possibly branch is, as it now 

 proves, in nowise to be confused with younger examples of 

 that species. Instead it clearly agrees specifically with those 

 notably beautiful branched trunks figured under the name 

 Cyeadeoidea Marshiana on Plate YI, figures 7 and 9, and on 

 Plates VII, VIII and IX, figure 1, of my American Fossil 

 Cycads (Structure). 



Conversely, the superb branching trunk figured by Ward J 

 and signalized as " the type " of Cyeadeoidea Marshiana has 

 not been found to present any real differences from Cyeadeoidea 



* Parts I-III of these studies of American fossil cycads appeared serially 

 in this Journal for March-May, 1899, Part IV in June, 1901, and Part V in 

 August, 1911. See also December, 1904 — The Proembryo of the Bennettiteas, 

 February, 1908 — Historic Fossil Cycads, and December, 1911 — On the 

 Williamsonian Tribe. 



f Ward, Lester F., Cretaceous formations of the Black Hills. Washington, 

 1899. 



JLoc. cit., Plates CI-CIII. 



Am. Jour. Sci.— Fourth Series, Vol. XXXIII, No. 194.— February, 1912. 

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