G. R. Wuland — American Fossil Cycads. 133 



Art. XIV. — A Study of Some American Fossil Oycads. 

 Part V* Further Notes on Seed Structures ; by G. R. 

 Wieland. 



[Preliminary publication by permission of the Carnegie Institution of 

 Washington.] 



Mainly in recent years through the continued study of the 

 wealth of fossil plants in the remarkable calcareous nodules or 

 " coal balls" of the Coal measures of England by the English 

 group of Paleobotanists, has the list of ancient seeds illustrated 

 in detail become a long one. In fact, material has so augmented 

 as to make the investigation of fossil seeds a subject of consid- 

 erable scope and even unique fascination and promise. 



So far, however, the best known old seed types are chiefly 

 gymnospermousand Paleozoic with the notable exception of the 

 Mesozoic Cycadeoideas. But fortunately whatever the latter 

 lack by reason of isolation they more than make up by abundance 

 and exquisite preservation in a half dozen different species. 

 Not only is the structural representation ample, but the num- 

 ber of mature strobili now runs into the thousands. In fact 

 the subject of Cycadeoidean seeds has assumed a continuous 

 interest. For in addition to the mature seeds we have the 

 seeds well outlined in many young strobili varying in size all 

 the way from a pea to a small pear, as well as a proembryonic 

 stage, considered present in one form (Gycadeoidea Macbridei % 

 Y. S. 131) ; while the fully developed dicotyledonous embryos 

 are finely conserved and have now been seen by thousands ! 



Yet for a number of years following Carruthers' (1) descrip- 

 tion of Bennettites Gihsonianus such material seemed exceed- 

 ingly rare, and it was not until 1894 that the isolated fruit 

 Bennettites (Williamsonia) Morierei (found by Moriere in 

 1865) was finally described by Lignier (3) in a memoir which 

 still retains its place as the most accurate detailed account of 

 the Cycadeoidean seeds so far given. Five years later the first 

 observation of seed cones on American trunks was announced 

 by Ward (5) and Wieland (6), while in the latter's volume on 

 American Eossil Cycads (8) a glimpse was had for the first 

 time of the great extent and variety of ovulate fructification in 

 the American species. 



And now, as if nature designed for the student of gymno- 

 spermous seeds " a beauty beyond compare," there has recently 

 been found near Hermosa in the eastern Black Hills Rim, by 

 Doctor Darton of the U. S. Geological Survey, half of a truly 

 monocarpic trunk now in the collections of the U. S. National 



* Parts I-III of these studies appeared serially in this Journal for March, 

 April, and May, 1899, and Part IV in June. 1901. 



Am. Jour. Sci.— Fourth Series, Vol. XXXII, No. 188. — August, 1911. 

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