CHAP. I. 
CELLULAR TISSUE. 
11 
is found in the pith of all plants ; and the rice paper, sold in 
the shops for making artificial flowers, and for drawing upon, 
which is really the pith of a Chinese plant, is an excellent 
illustration of it. If the force of extension or compression be 
greater in one direction than another, an endless variety of 
forms is produced, of which the following are the most worth 
noticing : — 
1. The ohlong ; in the stem of Orchis latifolia, and in the 
inside of many leaves. (Plate 1. fig. 9.) 
2. The lohed (Plate I. fig. 2./); in the inside of the leaf of 
Nuphar luteum, Lilium candidum, Vicia Faba, &c. : in this 
form of cellular tissue the vesicles are sometimes oblong with 
a sort of leg or projecting lobe towards one end ; and some- 
times irregularly triangular, with the sides pressed in and the 
angles truncated. They are well represented in the plates of 
Adolphe Brongniart's memoir upon the organisation of Leaves, 
in the Aiinales des Sciences^ vol. xxi. 
3. The square; in the cuticle of some leaves, in the bark of 
many herbaceous plants, and frequently in pith. (Plate I. 
fig.13.) 
4. The prismatical; in some pith, in liber, and in the vici- 
nity of vessels of any sort. (Plate I. fig. 6.) 
5. The cylindrical (Plate I. fig. 8. «); in Chara; this has 
been seen by Amici so large, that a single bladder measvn-ed 
four inches in length and one third of a line in diameter. 
{Ann, des Sciences, vol. ii. p. 246.) 
6. The fusiform or the oblong pointed at each end; in 
•wood, and in the membrane that surrounds the seed of a 
Gourd. These are what Dutrochet calls clostres. (Plate II. 
fig. 19. 8.; Plate I. fig. 5.) 
7. The muriform; in the medullary rays. This consists of 
prismatical bladders compressed between woody fibre or 
vessels, with their principal diameter horizontal, and in the 
direction of the radii of the stem. It is so arranged that 
w^hen 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 
