414 



related Batr. paucistamineum (Tausch) Gelert, from Denmark, 

 exhibited the following structure: The leaf-segments had be- 

 come oval in transverse section; there was only one bundle, 

 but the tissue on its upper side and partly also beside it had 

 developed into 1 — 2 palisade-layers, of which some individual 

 cells were about twice as long as they were thick; upon the 

 under side of the bundle the cells were more like those of 

 the aquatic leaf. Moreover, intercellular spaces were more 

 abundantly present in the mesophyll than in that of the aquatic 

 leaves. The radial walls of the epidermis were undulating and 

 the upper surface had as many as 80 stomata per sq. mm. 

 while many fewer (about 10 per sq. mm.) occurred upon the 

 lower surface. The Danish land-form had retained some chlo- 

 rophyll in its epidermis. The land-form had retained the water- 

 pores at the apex of the leaves. 



Aueraone Richardsoni Hook. 



Lit. Hooker, 1833. Lange, 1887. Janczewski^ 1898, p. 507. 



Alcohol material from Præstefjæld (Holstenborg), West Green- 

 land, 1884, and 4.8.1886. 



This species, like Л. nemorosa, is a perennial herb with 

 a horizontally elongated rhizome which becomes sympodial 

 when flowering begins. The principal bud is subtended by 

 the last leaf (Fig. 51, Ä). The rhizome may become very long 

 (20 cm.), and the length of the internodes is usually 1 — 3 cm.; 

 they are about Г5 mm. thick. The present species differs from 

 A. nemorosa not only in regard to the rhizome but also as 

 regards the leaves, the majority of them being foliage-leaves ; 

 Janczewski writes "all" but a specimen in the herbarium shows 

 one scale-leaf distinctly. The rhizome can produce at least 

 four foliage-leaves during one summer; they are iong-stalked 

 and the lamina is deeply 3-lobed with ovate, deeply-indented 

 segments. 



