PAPERS ON BOTANY 241 



is shown in Figure 1. In this the t^^^e form is that 

 labelled Sh. and E 74. C 19 represents a reduced size due 

 probably to lack of moisture and nutrition in extremely 

 exposed conditions on the sandy ridges. D-64 and A-8 

 show a characteristic which has always been associated 

 with the red oak (Quercus rubra) ; namely, the bulging 

 of the acorn about in the middle of its length which led 

 to the suspicion that D-G-t might be a hybrid. 



The variety depressa of Q. ellipsoidallis is shown in 

 Figure 2. This variety shows characteristics suggesting 

 the black oak (Quercus velutina) and some of the speci- 

 mens found might be hybrids of these two species. In 

 this figure D P a typical black oak is included for the 

 sake of comparison while H-27, very much dwarfed in 

 size, may be either a black or a peculiar ellipsoid. 



The distribution of the oaks is sho^\^i by the map in 

 Figure 3. The s^Tubols representing the different trees 

 were chosen with some care and experimentation to se- 

 cure a s^inbol which would be sufficiently small to fit in 

 ^-itli the scale of the map and yet be distinct to the eye. 

 Even with the size adopted it has proved impossible to 

 put one SATnbol for each tree observed, but instead an 

 attempt has been made to let the number of symbols for 

 each species be proportionate to the actual number of 

 trees of that species found. It was found that only five 

 or six s^TQbols could be relied upon. On account of the 

 small number of symbols available, it was impossible to 

 represent even all the species concerned, to say nothing 

 of the varieties of ellipsoid oak. 



A study of the map shows first, the transition from 

 ridge conditions to swamp conditions described by Miss 

 Sinmions. In this region no true ellipsoids were found 

 and the oaks were identified only as swamp white 

 (Quercus bicolor) or of the red-black type. The ellipsoid 

 oaks were found chiefly on the Calumet bar, although 

 some which are not recorded on the map were observed 

 on the Tolleston bar on the campus of Northwestern 

 University. This is left blank in the lower right hand 

 corner of the map as there was not time to study it 

 thoroughly before the acorns were removed either by 



