E. II. Sellards — Codonotheca. 87 



Aet. IX. — Codonotheca, a Neio Type of Sjpore-B earing 

 Organ from the Coal Measures '^"^ by E. .H, Sellards. 

 (Witli Plate YIII.) 



The iron-stone nodules of Mazon Creek, Illinois, which have 

 preserved so many interesting fossils, contain not infrequently 

 an isolated, but unique, and as yet undescribed type of fructi- 

 fication. The conditions of preservation in these nodules are 

 such that by careful developing it is possible to make out 

 many of the details of structure of the fossils contained in 

 them. In the present case, the abundance of material at hand, 

 and the unusual organization of the reproductive organ give 

 an especial interest to the study. It is the purpose of the 

 present paper to describe the structure of this peculiar type, in 

 so far as the material at hand will permit, in the hope that a 

 description of the fructification will lead to its recognition in 

 collections from other localities in this and foreign countries, 

 and to the determination of the plant to which it belongs. 

 The collections from the Mazon Creek locality in museums, 

 especially of this country, are generally quite extensive and 

 some of these may be found to contain specimens throwing 

 new light on the relation of this fructification. 



The spore-bearing organ is a symmetrical cup- or bell-shaped 

 body, made up of a circle of six equidistant, lamina-like, spore- 

 bearing divisions, arising at a common level, united laterally at 

 the base, free at the tips, thus surrounding a central cavity ; 

 each division is traversed on the inner or spore-bearing side 

 by two strong bundles supplied by the dichotomy of six main 

 strands ; the union of the laminse and bundles below forms a 

 cylindrical base, while the whole organ is borne on a slender 

 petiole. The base, which seems to have consisted for the most 

 part of an external envelope of non-resistant fleshy tissue, is 

 usually more or less completely flattened in the fossil condi- 

 tion. It is traversed by lines, often wavy and irregular, lying- 

 near the surface and extending along the dorsal side of the spore- 

 bearing divisions, probably representing subepidermal bands 

 of strengthening tissue. The fusion of the six main vascular 

 strands forms a cone-shaped area of resistant tissue at the 

 center of the base, large at the top where it breaks up into 

 strands, pointed below where it is replaced by less resistant 

 tissue. This area occasionally retains its cylindrical shape (figs. 

 1 and 11, PI. YIII). The six strands originating at a common 

 level from this central area diverge and dichotomize also at 

 approximately the same level. The twelve bundles formed by 

 this dichotomy pass into the six spore-bearing divisions, which 



* Abstracted from a thesis submitted to the Graduate Faculty of Yale 

 University, May, 1903, for the degi-ee of Doctor of Philosophy. 



