17 



grass which grows there in dense masses on the boundaries of 

 their forests, as containing free vascular bundles stretched from 

 one end of the joint to the other. The word free Is not used 

 here in the ordinary sense of a bundle ending free, but rather the 

 opposite. This bundle is described as a string or thread extend- 

 ing through the joint and, in its perfect condition, adhering at 

 both ends. Sometimes this string is tense, sometimes with coils 

 and spiral windings, fornn'ng a snarl of the different threads 

 which nearly fills the cavity. These grasses are said to reach the 

 height of two feet and over, and the length of the joints to vary 

 greatly. The seven lowest jomts of one stem are recorded as 

 varying from eighteen centimeters to f5ve- tenths of a centimeter 

 m length. They also vary in regard to the presence of the vas- 

 cular bundle. No rule could be found regulating the appearance 

 of these strings. They never occurred nearer the growing end 

 of the stem than the fourth or fifth joint, those above these being 

 solid ; anywhere else along the stem they were liable to occur. 

 The upper ones are described as transparent enough to allow 

 their structure to be determined without cutting. The bundle 

 consists of a central annular duct enclosed by two kinds of cells, 

 which are described as long with narrow diameter, the outer ones 

 being thin walled and whose long diameter is about twice that of 

 the other two dimensions. 



The author is unable to give any reason for the existence of 

 these threads, neither does he give the manner of their origin, 

 farther than to suggest that their growth does not take place 

 exclusively at the lower end. In conclusion he states that he 

 has sought in vain In the joints of many other grasses for this 



appearance; also in two other species of this same genus with 

 no result. 



E. L. G. 



M 



presence en Anjou de I'Equ 



314). Although 



[y. (Bull. Soc. Bot. France, xxxvi, pp. 312- 



reputed to be a rare species, Eqinsetnni littor- 

 ale, on account of its habitual sterility, has probably been much 

 overlooked. To distinguish it from E. arveiise and E. limoswn 

 with which it ordinarily grows, the following characteristics are 

 given : The central medullary canal is reduced to one-half the 



