LESQUEKEux.] TEETIAKY FLORA. 485 



of the fruits also. This hypothesis seems confirmed by the presence 

 of well-preserved branches of Taxodium distichum miocenicum, Heer, as 

 from the living Taxodium, it is seen that the fragments are mostly de- 

 tached and thrown upon the ground in winter time or early in the 

 spring. 



After the Plcmera leaves, those which are the most abundant in the 

 collection of Florissant are those of Myrica, two species, especially 

 Myrica acuminata, Ung., as represented in Tert. Flora, pi. xvii, figs. 

 1-4, a form somewhat different from that of Europe, and which seem 

 referable to two species of the Gypses of Aix, Myrica arguta, Heer, and 

 M. Zachariensis, Sap. ; the other, M. Ludwigii, Schp., a fragment of 

 which is figured in Tert. Flora, pi. Ixv, fig. 9. Other species of the same 

 genus are there also in a few specimens, especially Myrica latUoha, Heer, 

 var. acutiloba, same type as that of the Tert. Flora, pi. xvii, fig.13. The 

 leaflets of the species which is described in the same volume, p. 246, pi. 

 xliii, figs. 2-4, as Gallicoma micropJiylla, Ett., are as plentiful in 

 the collection as those of Myrica — perhaps more. Some are attached 

 to branches, and in their positions are alternate, distant, the upper 

 basilar side broader and rounded, the lower narrow, a disposition at 

 variance with that of the leaves of Myrica and of Rhus, the only genera 

 of our flora to which they might have been referred in their separate 

 state. And as Callicoma has in its species the leaves opposite, this 

 reference is still less admissible, though from our specimen it is not 

 possible to doubt the identity of the leaves with those described by the 

 German author under this name. I am unable as yet to decide upon 

 the true reference of these leaves, which, except the craspedodrome ner- 

 vation, have a great affinity to those of Myrica Saportwaa, Schp. They 

 are variable in size; some of them, the upper ones, are very narrow, 4 

 millimeters at the base, while others measure more than one centimeter. 

 The length does not differ comparatively to the width. .Their form and 

 disposition are like those of iSapindus or of ZantJioxylon. 



Briefly reviewing the plants of Florissant, in regard to the botanical 

 series to which they belong, I find a large number of the Amentacece in 

 the following genera : — Carpinus, two species, one referable to C. pyra- 

 midalis, Heer, the other to C. grandis, Ung. tflmus has a species of the 

 most common type of the Miocene, 77, Braunii, Heer, and another, refer- 

 able to U. Fischeri, Heer. Betula and Alnus are as yet indistinctly rec- 

 ognized ; two leaves seem referable to B. Bryadum, Brgt. Of Celtis. 

 there are leaves with entire and others with slightly dentate borders, 

 which have a great affinity to the present G. occidentalism and its variety 

 G. integrifolia, Nutt. They may, however, represent two species. Gory- 

 lus and Fagiis are absent. I can also scarcely separate as yet leaves 

 positively referable to Quercus. Populus has four species : one, P. latior, 

 a small leaf like the one represented by Heer as var. denticulata ; two 

 other distinct new species, one of the section of P. glandulifera, with 

 smaller, more acuminate leaves, without basilar glands ; the other, rep- 

 resented by two leaves still smaller, thin, or not coriaceous, 1^ centi- 

 meters broad, and as long, entire, with the base truncato-cordate, rap- 

 idly narrowing to a point, borne upon petioles about as long as the 

 leaves, slightly inflated at the point of connection to the lamina, lat- 

 eral primary nerves diverging at a broad angle, and secondary veins only 

 two pairs, parallel, and very thin. 



A fourth species is represented by a large number of leaves, remark- 

 ably different, in their size especially. They vary from 4^ to 23 centi- 

 meters long, and from 1 to 8 centimeters broad near the base, where 

 they are generally the largest, and there always rounded to a long, 



