144 STATION OF STOMATES. [BOOK i. 



in which statement he is supported by Schleiden, who seems 

 to think that the structure of the stomatic opening will be 

 modified according to the physiological peculiarities of parti- 

 cular species, and that it will often indicate affinity. He 

 mentions Indian Figs (Cactacese,) Conifers, Pepperworts 

 (Piperaceae,) Agave, with some allied Lilyworts, Spiderworts 

 (Commelinacese,) and Grasses, in illustration of this. (Wiegm, 

 Arch. 1838. p. 59.) Brown also remarks, that on the mi- 

 croscopic character of the equal existence of stomates on 

 both surfaces of the leaf depends that want of lustre which 

 is so remarkable in the forests of New Holland. (Journal of 

 the Royal Geogr. Society, i. 21.) 



These views are not, however, confirmed by more extended 

 observation. Take for example the following description 

 given by Zuccarini of the position of stomates on Conifers : 



"In the flat leaves they usually occur only on the dorsal 

 surface, on each side of the midrib, and form, as for instance 

 in Abies pectinata and others, between the rib and the 

 margin, two distinct white striae. In Sciadopitys, on the 

 other hand, the leaf is traversed by two parallel costae, 

 between which, instead of a midrib, is a strip of cellular 

 tissue, in which the rows of stomates are situated. In 

 Phyllocladus they are irregularly distributed between the 

 veins, all over the under surface of the leaf; whilst in Juni- 

 perus they occur on the upper surface, in a central tract. In 

 Thujopsis,on the contrary, and the K/etinisporse with adpressed 

 leaves and distichous branches, and in which the under side 

 of the leaf alone is ever visible, stomates occur on the surface 

 of all the leaves situated on the under side of the branch. 

 In those cases, however, in which the leaves are decussate, 

 the under leaf of that pair which is placed above and below, 

 is furnished with two rows of stomates, and none exist in the 

 upper; and whilst the inferior half of each of the leaves 

 constituting the lateral pair, which embraces the stalk, 

 presents stomates, there are none on the superior halves of 

 the same leaves." 



Brown is of opinion, that the two glands, or rather cells, 

 of which a stomate is composed, are each analogous to the 

 single cells often found occupying the inner face of the 

 meshes of the epidermis. (Plate III. fig. 9.) (See the 



