8 TRELEASE— LARGE FRUITED AMERICAN OAKS. [April 23, 



common to find a broad saucer-shape assumed with the fringe of 

 slender scales either seemingly absent, because closely inflexed beside 

 the acorn, or extended in its development over a considerable part of 

 the outside of the cup ; and it is even possible, as Professor Pieters 

 has recently shown me by material collected about Ann Arbor, for 

 the cup of the smaller type of fruit to be shallow and thin as in 

 the post oak, and either delicately ciliate at top or entirely without 

 a fringe even on a single tree. 



Even the largest acorns produced by these or our other familiar 

 oaks seem small when compared with those of some tropical species 

 of Quercus, or of the related genus Pasania. On our own conti- 

 nent, where the true oaks extend from the far north into the high 

 Andes of Colombia, these large-fruited species are of both the red — 

 and white-oak groups,— the former in Guatemala and Chiapas, and 

 the latter in the last-named state of Mexico and along the flanks 

 of the eastern Sierre Madre range above Vera Cruz. In contrast 

 with these, which may reach a diameter of 50 or even 60 mm., the 

 smallest acorns, also Guatemalan and Mexican, and of the group 

 of red oaks, scarcely measure 5 mm. in diameter.^ 



Some two years ago, while looking over a series of type photo- 

 graphs that I had made in the course of a systematic revision of 

 the oaks of tropical America, Mr. Walter Swingle, of the National 

 Department of Agriculture, expressed considerable interest in some 

 of the east-Mexican large-fruited white oaks as affording a hope- 

 ful field for experimentation both in direct propagation and hybrid- 

 ization, with reference to our own tropical and subtropical regions, 

 and Mr. David Fairchild, of the same government department, con- 

 sidered the matter of sufficient interest to undertake importations 

 through the interest of Dr. C. A. Purpus, whose collections in the 

 southern republic have done much of recent years to make its 

 vegetable wealth known. The purpose of the present communica- 



3 Quercus parviglans n. nom. — Q. niicrocarpa Liebmann, Overs. Dansk. 

 Vidensk. Selsk. Forhandl. 1854 : 184. — Liebmann-Oersted, Chenes Amer. Trop. 

 26. pi. 6. — Not Q. niicrocarpa Lapeyrouse, Hist. Abr. PI. Pyren. 582. 1813. 

 Equally small are the racemed acorns of an as yet unpublished group of west- 

 and south-Mexican species of the red oaks; and the east-Mexican white oak, 

 Q. glahrescens, possesses an equally small-fruited variety. 



