6 ON NAIAS G-RAMINEA DEL., VAE. DELILEI MAGNUS. 



Whether the plant found in Japan, at Yokohama, is identical 

 with Naias graminea Del. is uncertain, but the description of it oyHerr 

 C. J. Maximowicz may stand for the Lancashire plant :—" Mollis 

 elongata, foliis verticillatis patentibus rectis argute spinoso-serru- 

 latis, apice 2-3 cuspidatis, dentibus incurvis 1-cellulosis minutis ; 

 stipulis distinctimus lanceolatis foliaceis folii ad instar serrulatis ; 

 fructu lineari-oblongo, granulato. Nippon, in fossis circa Yoko- 

 hamam semel inveni fructiferam." * 



IV. — The Stem. 

 The stems vary in length from a few inches to upwards of two 

 feet, and they have many branches. Considering the large number 

 of leaves which they support, the stems are comparatively weak ; 

 they do not vary much in diameter from the base to the summit ; 

 vertical sections of the upper internodes are not quite so circular as 

 those of the lower internodes. 



Fig. 42. 



If we examine one of these internodes we find that the centre of 

 the shaft consists of a small channel, surrounded by two or three 

 layers of elongate cells somewhat closely aggregated ; surrounding , 

 these is a layer. of much larger cells, hexagonal in outline, and 

 having thinner walls than those which protect the central channel. 

 From this central mass radiates a series of from eight to twelve 

 prolongations of the central hexagonal cells, meeting as many out- 

 growths from the tissue which forms the circumference of the 

 internode, and arranged like the spokes of a wheel. See fig. 42. 



* Diagnoses breves plantarum novarum Japonic et Mandsohuria ; in Bulletin 

 de l'Acad. Imp. des Sciences de St. Petersburgh. Vol. ii., pp. 71, 72. 1867. 



