52 TRELEASE— NAMING AMERICAN HYBRID OAKS. 



X Q. subfalcata n. nom. (Q. cuneata X Phellos) 



This is Q. falcata Ashe, a preoccupied name. 

 X Q. subintegra n. nom. (Q. cinerea X cuneata) 

 X Q. sublaurifolia n. nom. (Q. cinerea X laurifolia) 

 X Q. Sudworthi n. nom. (0. cuneata X velutina) 

 X Q- TRiDENTATA Engelmann (Q. imbricaria X marilandica) 

 Q. velutina X cinerea= X Q. podophylla 



X CM;z^afa=; X Q- Sudworthi 



X ellipsoidalis=^ X Q- palgeolithicola 



X ilicifolia ^ X Q. Rehderi 



X imhricaria^= X Q- Leana 



X Phellos =X Q. dubia 



X rubra = X Q- Porteri 

 X Q. Walteriana Ashe (Q. Catesbcci X nigra) 

 Q. Wisliseni X Kelloggii^= X Q- moreha 



From the foregoing list, I have omitted Q. hemisphcerica Will- 

 denow and Q. hybrida Small, as I am frankly in doubt as to their 

 status. The latter (Q. laurifolia hybrida Michaux), supposedly a 

 cross between laurifolia and nigra, seems rather to be a toothed form 

 of 0. laurifolia. The former, comprising a great array of inter- 

 mediates between Phellos and nigra as well as other forms not other- 

 wise placeable, and in its extremes not distinguishable from these 

 species, though I do not recall that it has been held for a hybrid 

 seems more likely to include some hybrids in its complex than is 

 true of Q. hybrida. 



The University of Illinois, 

 March i, 1917. 



Explanation of Plates. 



Plate I. X Qucrcus palarolithicola. Type material in the Field Museum. 

 The upper figure about one third natural size ; the lower of natural size. 



Plate TI. X Quercus Schuettei, about one third natural size. The upper 

 sheet, in tlie United States National Herbarium, with foliage approaching 

 that of Q. bicolor; the lower, in the Field Museum, with foliage and fruit 

 more as in Q. macrocarpa. 



Plate III. X Quercus Schuettei. The upper figure a representation of 

 the type sheet, in the Field Museum, about one third natural size; the lower 

 a fragment of this specimen, of natural size. 



