THE PLANT WORLD 253 



and limbs are usually fairly covered with immense thorns. Where this 

 species grows isolated in fields and pastures, or is cultivated on lawns, 

 it grows into a beautiful well-formed rounded top, with long, gracefully 

 drooping branches, and frequently entirely free from thorns. The Water 

 Locust on the other hand is found only along the muddy borders of ponds 

 and bayous in alluvial bottom lands, where it stands in water most of the 

 year. It is a smaller tree, with more open and airy top. The bark is 

 smoother, the twigs and branches have more of a greenish tinge. The 

 thorns are also more slender but fully as long as in the former species. 

 The leaves vary considerabl}^ in both species, but in general features are 

 so much alike that it appears impossible to find a constant or reliable 

 difference. 



The only really constant distinctive difference is in the fruit. In 

 Gleditsia triacayithos the pods are many-seeded, of a dark, dull brown color, 

 from 6 to 15 inches, twisted and filled with a engary pulp. While in G. 

 aquatica the pods are iVi to 2/4 inches long, usually one-seeded, smooth, 

 shining and of a light brown color, not twisted and destitute of pulp. 

 The number of seeds is subject to occasional variation to two, and on a 

 few occasions I have found three seeds in one pod. The vicinity of Mt. 

 Carmel, 111., is the northernmost limit of this species so far as I can 

 learn. 



I have found here what appears to be two forms of hybrids. In one 



the pistillate plant appears to have been G. aqiiatica fertilized by G. tria- 



canthos. It stands in the muddy border of a pond, among a group of 



trees that are all true G. aquatica ; while G. triacayithos is some distance 



away on higher ground and sandy soil. In the second case the tree grows 



in a group of G. triacanthos , and it stands in a sandy ridge about 500 



yards distant from a pond where grows G. aquatica. In both instances 



the pods are the distinguishing feature. These are very much alike in 



both trees ; being about 5 inches long, lY-z inches wide, smooth, shining, 



of a light brown color and entirely destitute of pulp. Otherwise the trees 



can not be distinguished from the trees among which they stand. They 



are both about 50 feet high, with short stems and spreading branches, 



and stand about 5 miles apart. J. Schneck. 



Mt. Carmel, 111. 



The Commercial Status of Durum Wheat ' ' is the title of a very 

 interesting paper by Messrs. Carlton and Chamberlain, which relates to 

 the introduction in this country, and the increasing value of, macaroni 

 or ' ' durum ' ' wheat. Besides treating at length on the value of this grain 

 for bread-making, the paper is specially valuable for collating numerous 

 recipes for cooking semolina and macaroni, the two best known products 

 of durum wheat. M. 



