THE AMERICAN BOTANlS'i 69 



into useful strains. The form is discussed in Bulletin 925 of 

 the United States Department of Agriculture. 



A New Form of Dentaria. — About five years ago, Mr. B 

 O. Wolden of Wallingford, Iowa, sent us living specimens of 

 a curious form of toothwort {Dcntaria laciniata) which had 

 two sets of stem leaves instead of the usual single whorl. This 

 year the form has fruited in our grounds and proves to be 

 very much like the common form with the exception noted. 

 This double set of stem leaves appears to be constant and since 

 new species in this genus have been made on much smaller dif- 

 ferences in leaves, it appears desirable to give this form at 

 least a varietal name. It is here proposed to call it Dentaria 

 laciniata z'ar. dichronum. The root leaves and stem leaves are 

 similar, those of the lower whorl being rather broader than in 

 the common form. They are borne on petioles four inches or 

 more long which arise from the stem about two inches from the 

 ground. The second whorl of stem leaves is located midway 

 betwen the lower leaves and the flower-cluster. They are on 

 petioles about an inch long and similar in appearance to the 

 lower leaves though somewhat, smaller, those who prefer to 

 call this a species would name it Dcntaria dichronmn, the spe- 

 cific name alluding to the two shades afforded by the two sets 

 of leaves. The plant is reported to be fairly common about 



the type locality, Wallingford, Iowa. 



Rhubarb Leaves Poisonous. — The common pie-plant or 

 rhubarb {Rlicinn rhaponticum) of our gardens so universally 

 used as the basis for pies and sauces in early spring is reported 

 to contain a certain percentage of the deadly poisonous oxalic 

 acid. It has long been assumed that this acid wa^ present in 

 the stalks along with malic and citric acids, but it does not oc- 

 cur here in (juantities that makes it harmful. In the l)lades 

 of the leaves, however, the acid is reported to be twice as abun- 



