STRUCTURE.] STOMATES FALSE WHEN PRESENT. 143 



two-celled hair. These have been taken for stomates by 

 Meyen, in a plant called by him Pleurothallis ruscifolia 

 (Wiegmaris Arch. 1837, t. 10, figs. 4, 5, 6, 7, 8, 9) ; but 

 according to Schleiden, the observations of this anatomist 

 are incorrect, and all such appearances are either spaces left 

 by the fall of hairs, whose bases fitted into the cavity, or 

 formed for the reception of hairs, or depressions of an entirely 

 different nature from stomates. 



Stomates are not found in Fungals, Algals, or Lichens (see 

 Vegetable Kingdom, THALLOGENS) ; in no submersed plants, 

 or submersed parts of amphibious plants. They are not 

 formed in the epidermis of plants growing in darkness, nor 

 upon roots, nor the ribs of leaves. It frequently happens 

 that they are found upon one surface of a leaf, but not on 

 another, and generally in most abundance on the under side. 



In succulent parts they are neither rare nor wholly want- 

 ing, as has been often asserted ; but are, on the contrary, as 

 numerous as on many other parts. They may be generally 

 seen upon the calyx ; often on the corolla ; and rarely, but 

 sometimes, upon the filaments, anthers, and styles. In fruit, 

 they have only been noticed upon such as are mem- 

 branous, and not upon the coat of the seed ; not even upon 

 those seeds which, as in Leontice thalictroides, grow exposed 

 to air; with the exception of the genus Canna, in which 

 Schleiden has found them, and to which he thinks them 

 necessary in order to facilitate the passage of fluid into the 

 interior of the seed. They exist upon the surface of coty- 

 ledons. 



Their existence has been denied in Mosses ; in which, 

 however, M. Valentine has found them. Endlicher also says 

 that Isoetes has no stomates ; De Candolle figures them in 

 that plant in his Organographie ; and Mr. Griffith remarks 

 that in I. capsularis they are very evident. This observer 

 adds, that no matter, whether emerged or submerged, all 

 plants having an epidermis have stomates. 



Brown thinks that the uniformity of the stomates, in figure, 

 position, and size, with respect to the meshes of the epidermis, 

 is often such as to indicate the limits, and sometimes the 

 affinities, of genera, and of their natural sections. He has 

 shown, with his usual skill, that this is the case in Proteads, 



