Occurrence of Foliaf/c-karcfi in Ruscus androgynus. 145 



general induration. The third and outermost layer of the 

 cndodermis is usually well raarked. The xylem ducts 

 are comparatively small, and are not very numerous. — 

 Specimens from the Glasgow Botanic Garden exhibit 

 almost exactly the same characters.* 



In Plate XL fig. 2, is represented a similar section from 

 a plant in the garden of Miss Hope at Wardie, Edinburgh. 

 Hero the tissue elements are not so numerous, but are 

 of considerably larger size, and are relatively much less in- 

 durated. The third and outermost layer of the endodermis 

 is almost completely undeveloped, as will be seen from the 

 figure, where only one cell of this layer is to be seen. — 

 Specimens from Trinity College Botanic Garden, Dublin, 

 correspond with this type. 



In Plate XL fig. 3, is represented a section from the 

 plant in the Royal Botanic Garden, Edinburgh. The roots 

 here are altogether a good deal larger than in either of 

 the preceding forms. The endodermis exhibits all the 

 three layers distinctly developed, but with only a moderate 

 amount of induration. The xylem prosenchyma is less 

 indurated than in my plant, but more so than in Miss 

 Hope's one. Perhaps the most striking peculiarity of this 

 third form is to be seen in the xylem ducts, which are 

 numerous and of great size. — Specimens from the Royal 

 Gardens, Kew, which I owe to the kindness of Sir J. D. 

 Hooker, correspond with this type. 



The figures I have drawn will give a much better idea 

 of these remarkable variations in root structure than any 

 further description. They may possibly be found to be 

 correlated with other varietal differences ; or they may 

 to a certain extent depend on circumstances affecting the 

 general vigour of the plant. But for the present I must 

 leave such questions unsolved. 



Postscript. — April 1885. 

 The substance of the foregoing paper was communicated 

 to the Society in July 1883 ; and a short abstract was pub- 

 lished soon afterwards in the Gardeners Chronicle^ July 28, 

 1883. In various respects, I liave considerably expanded 



* Unfortunatelj-, I cniinot remember whence I obtained my own plant of 

 Ruscus andwgi/nus. It seemed not improbable that I had got it from 

 Glasgow ; but Mr Bullen, the Curator of the Garden there, thinks this impos- 

 sible, as he has never until quite recently attempted to propagate his plaiit. 



TRANS. BOT. SOC. VOL. XVI. K 



