366 MESSES. CTEIL WEST AXD H. TAKEDA ON 



Systematic Observations. 



* 



A. Eraun (4), describing the present species for the first time, expressed the opinion 

 (/. c. p. 460) that it helons^ed to his section "palustres s. amphibise " of the genus Isoetes. 

 In a later and more detailed account of this species the same author (5, p. 8) retained 

 this classification*. Some years later, in 1882, Motelay and Vendryes (25, p, 318) 

 placed this species ia their section " palustres," which, together with the section 

 " amphibiae," they had established on the above-mentioned group of A. Eraun. Eaker 



p. 132), on the other hand, transferred it to the group " Amphibise " f. Sadebeck 



(27), in a more recent work on Isoetes, placed I.japonica in the section "amphibise," 

 following A. Eraun in his classification of the genus. 



We are perhaps justified in taking advantage of this opportunity of discussing the 

 classification of this genus. 



A brief summary of the various classifications which have been put forward is given 

 below in order of priority : — 



1. Alex. Eratjn (5, p. 8; 6, p. 598), followed by Milde (23) and by Sadebeck (27). 



Section 1. Aquaticae (s. Submersse). 



Leaves with wide lacunae, the outer wall of which, including the epidermis, 

 consists of from 2-3 layers of cells ; stomata, hypodermal fibres, phyllopodes, 

 and pliy Hades (" Niederblatter ") absent. 

 Section 2. Ampliibise (s. Palustres). 



Leaves as in 1 ; but with stomata and groups of hypodermal fibres, usually 6 



in number. Phyllopodes and phyllades absent. 

 Section 3. Terrestres. 



Leaves with narrow lacunae, the outer wall of which consists of only one 

 layer of cells, i. e. the epidermis itself ; stomata numerous ; 4 large groups of 

 hypodermal fibres ; phyllopodes and phyllades present. 



2. MoTELAT and Yendeyes (25, p. 817). 

 Group 1. Aquaticae. 



Section 1. Submersae. 



■ 



Leaves with wide lacunae, the outer wall of which consists of from 2-3 

 layers of cells. Phyllopodes and phyllades absent. 

 Section 2. Palustres. 



Leaves as in 1 ; but 6 groups of hypodermal fibres present without exception. 

 Phyllopodes absent. Phyllades absent, or, if present, very feebly developed. 

 Section 3. Amphibiae. 



Leaves as before, with 6 groups of hypodermal fibres ; stomata usually 

 present. Phyllopodes and phyllades absent. 



* In an appendix to the paper, Braun refers to this section as " Palustres s. Immdatse " (?. c. p. 33). 

 t Baker established a fourth group, " Suhaquaticse," characterized by the presence of stomata and the absence of 

 hypodermal strands. 



