DISTRIBUTION OF RHAMNUS IN NORTH AMERICA. 133 



abruptly truncate at the apex, where they suffer erosion. 

 The younger ones are rounded at the apex before erosion 

 begins. The margins are provided with coarse, sharp teeth 

 and the surfaces are coarsely and longitudinally rugose much 

 as in Macrocystis. 



The older sporophylls at the true outer (or upper) portion 

 of the margin of the ligule, are mere stubs, being eroded 

 nearly to the base. The middle ones are longer but the true 

 outer (or lower) ones become smaller and smaller, until at 

 last they are mere protuberances from the margin. This 

 shows that the sporophylls are true out-growths from the 

 blade and proves also their Ecklonioid character. The 

 sporophylls of many of the specimens collected by the writer 

 at San Pedro and Kedondo in December, 1895, were in fruit. 



E. SORI. 

 The sori do not form extensive and uniform patches cover- 

 ing completely the sporophylls as they do in Alaria, but are 

 small and oblong or irregularly elliptical in shape, a few 

 centimeters long and proportionally narrow. As they con- 

 tinue to be produced, they become confluent into fairly large 

 patches of irregular outline nearly covering the entire sur- 

 face of the older sporophylls. The unilocular sporangia 

 and the unicellular paraphyses are of the usual type found 

 in the Laminariaceae. 



(To he concluded.) 



DISTEIBUTION OF RHAMNUS IN NORTH 

 AMERICA.— II. 



By Edwakd L. Greene. 



I must here at the outset correct a statement made in the 



preceding paper i; for I therein remarked that the Rocky 



Mountain region had no representative of true Mhamnus, 



save as R. alnifolia was found in the northern sections of 



iSupra, p. 83. 



