A Monograph of the Genus Alarla. 53 



The first-year fronds of Alaria found in summer liave general- 

 ly much narrower and thinner blades when compared with the 

 second-year ones. Some of them may have small sporophylls 

 which become soriferous and discharge the spores late in autumn J) 

 The thin and narrow blade is worn aw^ay for the greater part of 

 its length. 



In the following year, during March and April in the warmer 

 parts and gradually later in the colder north, the blade begins its 

 sudden growth, and sporoi)hylls of normal size make their appear- 

 ance above the smaller ones of the preceding year, quickly in- 

 creasing in number successively upwards. The sporophylls of the 

 preceding year drop off one by one from below, leaving verrucose 

 scars on the stipe (Plate X). The blade now built up is thicker 

 in substance and darker in colour than that of the preceding year. 

 The sporophylls attain their full maturity in the latter part of 

 spring and then the life of the plant terminates within a few 

 months. Thus it exists for two whole years, but not longer. 



The life history alluded to above holds good, as far as I could 

 find, for all species found within our boundaries. Even such a 

 gigantic form as A. fistulosa shows only a slight modification if 

 any. The marvelous size of the blade of this species is therefore 

 nothing but the result of the speedy growth during 5-6 months. 



As far as I could refer to, full evidence for the perennial life 

 of the Alaria plants has never been positively given by any algo- 

 logist, although there have been many who describe them to be 

 perennial. Wille^) relates:— "Dass im Stipes ein sekundäres Längen- 

 wachstum vor sich geht, jedenfalls oben und bis unterhalb der 

 ältesten Sporophyllen, konnte mit Sicherheit an Exemplaren nacli- 



1) AVn,LE : Beiträge z i)''ysiol. Anatom .der Laminariaceen, i>. 16. 



2) Wille : 1. c. 



