CHAP. I. 
CELLULAR TISSUE. 
15 
prismatical bladders compressed between woody tissue or 
vessels, with their principal diameter horizontal, and in the 
direction of the radii of the stem. It is so arranged that 
when ' viewed laterally it resembles the bricks in a wall ; 
whence its name. (Plate I. fig. 7.) 
8. The compressed ; in the cuticle of all plants. Here the 
bladders are often so compressed as to appear to be only a 
single membrane. (Plate I. fig. 2. a; Plate III. fig. 3, 4, 
&c.) 
9. The sinuous ; in the cuticle, and also sometimes beneath 
it, as in the leaf of Lilium candidum. (Plate III. fig. 5.) 
10. The stellated; where the cells are so deeply lobed at 
the angles as to leave open passages between them, as in the 
stem of Eriophorum vaginatum. Plate III. fig. 2. is an ap- 
proach to this structure. 
11. The tabular ; as in the epiphlaeum of many plants. 
Cellular tissue is frequently called Parenchyma. Professor 
Link distinguishes Parenchyma from Prosenchyma ; referring 
to the former all tissue in which the bladders (Plate I. fig. 1, 
3. 6, 7, &c.) have truncated extremities ; and to the latter, 
forms of tissue in which the bladders taper to each end, and, 
consequently, overlap each other at their extremities. 
Meyen has Merenchyma, for ellipsoidal and spheroidal cells ; 
Parenchyma for angular cells ; and Prosenchyma as above de- 
scribed. 
Fibro-cellular Tissue is that in which the sides are 
composed either of membrane and fibre together, or of fibre 
only. 
It is only lately that this kind has been recognised. The 
first observation with which I am acquainted is that of Mol- 
denhauer, who, in 1779, described the leaves of Sphagnum 
as marked by fibres twisted spirally. {Fig^ 3. a, p. 9.) In 
November, 1827, I described the tissue of ^aurandya Bar- 
clayana as consisting of bladders formed of spiral threads 
crossing each other, interlaced from the base to the apex, and 
connected by a membrane. A few other solitary cases of this 
kinds of tissue had subsequently been observed when the 
investigations of a modern anatomist suddenly threw an en- 
tirely new light upon the subject. 
