Nov., 1904.] Twigs of the Coinmon Haekberry. 215 



A number of nutating plants have been studied by the writer 

 in the past and during the present year observations were con- 

 tinued on various species which it was thought might show the 

 pecuHartv. The following six species show a movement of the 

 stem tip and terminal leaves when conditions are favorable. 



Chenopodium album L. 



Polygonum lapathifolium L. 



Polygonum pennsylvanicum L. 



Euphorbia hexagona Nutt. 



Euphorbia dentata Mx. 



Iva ciliata Willd. y^'^W / 



The two Euphorbias have a very decided nutation, the curvaCN/ . ^o* / 

 ture of the stem often being as great as in the Sunflower. /v^ ^^-^.•-* 



luJ ( L I B R A 



TWIGS OF THE COMMON HACKBERRY. 



John H. Schaffner. 



Our Hackberries demand careful study in the field in order 

 that some of the obscurities may be removed which now appear 

 in the descriptions of our Manuals. Celtis occidentalis L. is said 

 to have ''glabrous twigs" and "leaves smooth above." Celtis 

 crassifolia Lam. is said to have "the young shoots puberulent" 

 and "leaves scabrous above." Now, we can find all of these 

 characters on different twigs of the same tree. 



So far as Celtis occidentalis is concerned, I have not found a 

 Haekberry in Ohio or Kansas that did not have pubescent twigs. 

 The tree has two types of twigs; fruiting twigs and twigs which 

 bear no flowers. The fruiting twigs have a few scattered hairs 

 when young but these usually fall off early. The leaves are very 

 glabrous above and of a peculiar appearance. These fruiting 

 twigs dry off at the outer ends while the fruit ripens and they are 

 then very abundantly detached, a brittle layer being developed 

 at the base. Often the twigs come down with the drupes still 

 attached. The purely vegetative shoots are usually quite pube- 

 scent when young, the pubescence extending to the leaves. In 

 most cases the pubescence is persistent on the twigs and the 

 mature leaves are quite scabrous or hairy. As one goes west- 

 ward the pubescence of the vegetative shoots appears to become 

 more pronounced, and one can find trees with very smooth 

 fruiting twigs and very hairy vegetative twigs. 



Are there any characters to establish the species, Celtis cras- 

 sifolia Lam. ? From an examination of supposed C. crassifolia 

 and C. occidentalis identified by competent botanists I can find 

 noTspecimens in either set which cannot be duplicated by twigs 



