82 The Plant World. 



An electric valve and automatic recorder may be introduced 

 between vial C and the reservoir, or tube E may be partly of 

 rubber and the reservoir may stand on a recording balance in a 

 suitable shelter, thus rendering the instrument self-recording. 

 Without the automatic removal of absorbed rain water the re- 

 cording apparatus is always thrown out of function by any 

 but slight showers. The present instrument will register or 

 record evaporation as long as absorption by the cup does not 

 equal or exceed its water loss. Thus, during a slight shower in 

 an arid region, evaporation may continue to some extent through- 

 out the precipitation period, especially if wind prevents the 

 surface of the cup being uniformly covered with a water film. 

 The Johns Hopkins University, 



Feb. 26, 1910. 



AN ABERRANT WALNUT. 

 By Ira D. Cardiff. 



In the fall of 1903, a peculiar nut was sent from northern 

 Indiana to Professor C. R. Barnes of the University of Chicago. 

 The nut was borne on a tree which is walnut (Juglans nigra) in 

 most, if not all, of its other characters so far as has been ascer- 

 tained. This was said to be one of a number of such nuts which 

 had been borne on this tree. The nut itself, externally at least, 

 is very different in appearance from a walnut. It is' divided 

 transversely into two almost equal halves. The basal half, or 

 that portion which is attached to the stem, resembles a walnut 

 having a glabrous, roughly dotted, somewhat spongy hull. 

 Upon drying it becomes regularly wrinkled and roughened with 

 small pits and elevations. The opposite half, on the other hand, 

 possesses a smooth exocarp of firm texture, without dots, and 

 remains smooth upon drying. Furthermore, this outer half 

 is marked by four deep furrows running longitudinally and con- 

 verging at the apex like the four halves of a hickory nut exocarp. 

 In fact this half of the nut has, externally, all the appearance of 

 a hickory nut, though the furrows above mentioned do not ex- 



