788 ORIGIN AND DEVELOPMENT OF STOMATA. 
seems to be possible under certain circumstances. Various 
experimenters have endeavoured to show that they have this 
power. The researches of Garreau led him to the following 
conclusions :—1. That the epidermis possessed an evident endos- 
motic property, the intensity of which was in proportion to 
the age of the tissues which it invested; thus it was greatest 
when they were young, gradually diminished as they approached 
maturity, and was altogether lost when they became old. 2. The 
absorbing power of the epidermis was greater in proportion to 
the absence of waxy or fatty matters. 3. The epidermis cover- 
ing the upper surface of the ribs, and especially of that of the 
petiole where it joins the stem, is that part of the leaf surface 
which presents the most marked power of absorption. 4. In 
certain instances in which the epidermis is absorbent, the cuticle 
presents impediments to absorption. 5. Simple washing with 
distilled water, and more especially with soap and water, aug- 
ments the absorptive power. 6. When the epidermal tissues of 
leaves have lost their power of absorbing water, they can still 
absorb carbon dioxide. Further, the behaviour of Carnivorous 
Fig. 1143. 
Fig. 1143. p, p. Parenchyma of the leaf. e,e. Epidermis cells. s. Stoma. 
i. Air cavity. In these figures the development of the stoma of Hyacin- 
thus orientalis is represented from the first division of the mother-cell in 
A into two daughter-cells, to the complete separation shownin D, (After 
Sachs.) 
Plants, as Drosera, Utricularia, &c., seem distinctly to prove the 
truth of the power of epidermal tissues to absorb nutrient 
materials in solution. 
Origin and Development of Stomata.—A stoma is formed by 
the division of an epidermal cell (the mother-cell) by a partition 
which extends across and divides the two daughter- or sister-cells 
(fig. 1143); this partition then becomes thickened, especially at 
the angles where it joins the wall of the parent-cell. After a 
time the thickened partition becomes laminated, when a cleft 
appears in it, narrower in the middle, wider without and within, 
which unites the intercellular space (fig. 1143, p, s, t) with the 
external air. Before the parent-cell divides, a cuticularisation 
of its surface takes place, the cuticle extending over the apposed 
surfaces of the sister-cells, and the adjoining cells of the epi- 
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