287 
Ipomoca paniculata. 
or six layers of cells in the narrowest part separate the 
glandular epithelium from the starch-sheath of the vascular 
cylinder ; but no starch could be detected in the intervening 
cells. When the leaf shows signs of decay and begins to 
turn yellow, sections of the gland show that the epithelial 
cells undergo degenerative changes, and become filled with 
oil-globules. Oil is also found then in the surrounding 
parenchyma. 
EXPLANATION OF FIGURES IN PLATE IX. 
Illustrating Miss Ewart’s paper on the Leaf-glands of Ipomoea. 
Fig. 1. View of glandular region of mature leaf whose lamina measured 10 cm. 
from base to apex. Drawn from lower surface, right-hand side, m, midrib; 
e, margin of leaf-lamina ; c, projecting cushion of tissue ; /, papilla ; d , aperture 
of duct ; s, petiole. 
Fig. 2. Do. left-hand side, to show two papillae,/. 
Fig. 3. Left-hand glandular region of younger leaf, whose blade measured 8 cm. 
from base to apex. 
Fig. 4. Tangential section of papilla, near surface, from leaf whose lamina 
measured 1-5 cm. d, duct; /, small cells forming papilla and walls of duct, 
derived from epidermis ; t , surrounding leaf-parenchyma, derived from ground- 
tissue. 
Fig. 5. Longitudinal section of mature gland whose external surface is repre- 
sented in Fig. 3. 
In this and the following figures the lettering has the same significance. 
d, mouth of duct ; p, tissue forming papilla, derived from epidermis ; s. e, secretory 
epithelium ; has 1 , supporting cell on which the secretory epithelium rests, derived 
from epidermis ; bas 2 , second supporting cell, below bas 1 , derived from epidermis ; 
/, small-celled parenchyma, forming the ‘ packing ’ of the gland, derived from 
ground-tissue ; r, roof of gland, formed by proliferation of epidermal cells lining 
duct ; /, lumen of gland ; n , nucleus. 
Fig. 6. Diagrammatic transverse section of very young leaf of axillary bud, 
whose blade was about 1 mm. in length, through glandular region, gl , small 
surface-glands ; vb, vascular bundles. 
Fig. 7. Do. left glandular invagination more highly magnified. 
Fig. 8. Transverse section through gland of older leaf of bud (blade equals 
2*5 mm. long). 
Fig. 9. Longitudinal section through the other gland of same leaf. 
