Notes . 
i 27 
The under epidermal cells are of the usual wavy type with many 
stomata. 
Polemonium caeruleum.— The cotyledons of Polemonium caeruleum 
have stomata on their upper surfaces, except over the apical patch, 
which is also destitute of water-pores. The epidermal cells and 
stomata of the under surface are of the usual type. Near the apex 
of the under surface are five or six water-pores. This plant, therefore, 
forms an exception to the foregoing types in having its water-pores 
on the under surface. 
Convolvulus major (Figs. 4, 5). — The cotyledon is bilobed in 
Convolvulus major. Ordinary stomata are found on the under ; much 
fewer on the upper surface. The median vein branches dichotomously 
Fig. 4. Cotyledons of Convolvulus major, showing regular intercellular spaces 
among the palisade parenchyma. Large regular intercellular spaces, surrounded by 
palisade parenchyma, appear in polygonal areas near the apex of the cotyledon. 
Spiral vessels form the boundaries of the areas. 
before reaching the base of the apical sinus, and sends a branch into 
each of the lobes. Between the base of the sinus and the forking of 
the vein is a triangular area which is divided into a number of polygonal 
spaces by means of a network of spiral vessels. In the middle of each 
space is a cavity which displaces, and is surrounded by, palisade 
parenchyma. Some of these cavities are separated from the upper 
epidermis by a single layer of palisade parenchyma ; others have no 
palisade- cells between them and the upper epidermis; but none have 
been observed to open through the epidermis. A spiral vein has been 
indicated, in the horizontal section, passing from the polygonal 
boundary of one of these areas towards the cavity; and the ending of 
a spiral vein is seen in one of the cavities in vertical section. Each of 
these cavities seems to be an epithem, but no true stoma has been 
observed leading from the cavity. 
