The Structure of the Cork Tissues in Roots 
of Some Rosaceous Genera. 
(WITH PLATE X.) 
By Martua Buntine, Pu. D. 
N his paper upon “ Plant Hybrids ”’* Professor J. M. Macfar- 
| lane noted the presence of intercellular spaces in the cork 
region of the roots of Geum urbanumand G. rivale. While I 
was studying at the University of Pennsylvania during the sum- 
mer of 1895, he suggested that I should try to ascertain whether 
the existence of intercellular spaces in the cork region was a 
definite character of the roots of Rosaceous genera. Since 
the summer of 1895 the study has been continued at intervals 
at the University of Pennsylvania and at the Woman’s College 
of Baltimore. I wish to extend my thanks to Professor 
Macfarlane for his ever ready assistance and criticism of the 
work, as well as his very generous supply of material from the 
Botanical Garden of the University. 
In addition to the paper already noted, I have found refer- 
ence to intercellular spaces, in the cork region of Rosaceous 
genera, only in the following quotation taken from Vines’ 
text-book of Botany, published in 1895: ‘‘ The cells of the 
periderm are not always completely suberized. In some cases 
(roots and stems of Oxagracee, Hypericacee, some Rosacea, 
etc.) some layers of the periderm consist of cells with a 
suberized zone like that of the cells of the endodermis, though 
these cells usually become completely suberized eventually. 
In other cases (¢. g., stem of Poterium, Alchemilla, Agrimonia, 
Epilobium) the periderm consists mainly of cells with cellulose 
* Trans. Roy. Soc., Edin., Vol. xxxvii, 1892. 
54 
