M. J. Munter on the Structure o/Nuphar lutea. 237 



centric ; at the bottom of the pit a bundle of woody fibres, broken 

 off, but still somewhat projecting, like the ligamentum teres of 

 the human acetabulum ; the surface of the pit between this woody- 

 bundle and the ring-shaped scar is smooth, and presents nothing 

 remarkable. As regards the nature of these elegant pit-like scars, 

 by comparing all parts of the surface we soon perceive that they 

 owe their origin to roots, which separate spontaneously ; this view 

 is confirmed by tracing the course of the separation. Even whilst 

 the root is perfectly entire, the bark of the stem is raised from 

 the surface of the latter, and gives rise to the above-mentioned 

 limb. The concentric ring on the inner surface of the pit is 

 formed by the separation of the bark of the root from that of the 

 stem, and the broken-off woody bundle found in the bottom of 

 the pit was previously continuous with the central woody bundle 

 of the root. 



Besides this interesting formation of scars from the spontaneous 

 separation of roots, a phsenomenon which I have never elsewhere 

 observed, the solid contents of the cells of the highly developed 

 pith excited particular interest. 



If we examine microscopically that portion of the stem most 

 remote from the buds placed on the summit, we find that the 

 contents of the cells do not assume any definite shape, but form 

 a parenchymatous tissue filled with water or air. At the distance 

 of 2 — 3 inches, however, and especially just beneath the buds on 

 the summit, all the cells of the pith are filled with a solid sub- 

 stance which has a definite form, is coloured blue on the addition 

 of aqueous solution of iodine, and consequently agrees in proper- 

 ties with starch. As regards the forms of the particles, some are 

 simple, more or less rounded cells ; others are hemispherical, and 

 formed of two grains lying in contact like rolls ; again, others 

 form segments of circles, and derive their shape from the union 

 of three double grains, and are arranged either in a linear or 

 superficial manner : we also observe granules which are formed 

 from the union of four, and finally perfect penta- and polyhedra. 



Whilst these forms agree most distinctly with those of the 

 starch particles which I found and described in Gloriosa superba, 

 their size forms also another point of similitude ; it cannot indeed 

 be asserted that the Nuphar starch in general exhibits such 

 large particles as the Gloriosa, but it most resembles it in the 

 relative size of the separate granules ; in it the internal layers are 

 as sharply outlined as in the Gloriosa starch, and thus afford a 

 good substitute for the latter, which is so difficult to obtain. For 

 this reason I recommend the Nuphar starch as an excellent ex- 

 ample for those who have occasion to demonstrate microscopi- 

 cally ; and also to those who may think it worth while to test my 

 view of the centripetal formation of the starch granules, as I am 



