254 
Fig. 8. 
ON CAOUTCHOUC-CONTAINING CELLS OF EUCOMMIA ULMOIDES, OLIVER. 
DESCRIPTION OF THE PLATES. 
Рілте LVII. 
. Longitudinal section through the cortex of а young internode, showing two initial cells with 
dense protoplasm surrounded by the loose cortical cells. These latter possess a vacuole and 
plastids, which are not present in the initial cells. 
. Two initial cells in the more closely packed cells of the petiole of a young leaf. 
. Initial cells in the pith of Eucommia, showing commencement of elongation. 
. Initial cells in the cortex beginning to elongate at one extremity, and showing the formation of 
the vacuole. 
. А group of very young caoutchouc-containing cells, showing their elongation in two directions. 
The larger granules in these cells are grains of caoutchouc, the smaller ones protoplasmic 
granules. Тһе two lower cells have been derived from one mother cell. 
. Тгапзуегзе section of a young internode. Тһе cortical tissue has large intercellular spaces, іп 
which the young caoutchouc-containing cells can be seen in pairs. The larger cells are 
those which have been cut through in the region of the nucleus. 
. Transverse section through an older internode, in which the caoutchouc-containing cells have 
become more separated one from the other, and show clearer contents owing to the consoli- 
dation of the caoutchouc granules into a homogeneous mass. | | 
Longitudinal section through an older internode, showing the course of the caoutchouc cells 
through the very loosely packed cortex. 
Pirate LVIII. 
Fig. 9а,6, & с. Different stages in the consolidation of the caoutchouc granules. In а the granules 
are not very numerous ; in 0 they almost fill the cell; and in c they have become fused into 
а single mass. 
Fig. 9 d. Cell from the phloem of a young internode, in which large grains of caoutchouc make their 
Fig. 10. 
appearance within the primordial utricle. 
Bulbous dilatation by which many of the caoutchouc cells terminate in the cortical and other 
tissues, 
Fig. 11. Bulbous dilatation which is not terminal. 
Fig. 19. 
Fig. 13. 
Fig. 14. 
Fig. 15. 
Tooth of a young leaf after treatment with sulphurie acid. Тһе leaf is rendered transparent, 
and shows the irregular bulbous terminations of the caoutchouc cells. ; 
Longitudinal section of tooth of young leaf, showing the termination of two caoutchouc cells. 
Transverse section of the secondary phloem of Eucommia. The caoutchouc cells are seen 
running between the sieve tubes and the companion cells. The sieve tubes have their sieve 
plates on the radial walls. m.r. median тау; в.р. sieve plate; c.c. caoutchouc cell. 
Longitudinal section of the secondary phloem, showing the course of the caoutchouc cells. 
Sieve plates are seen in surface over and in section. 
(Figs. 14 and 15 have been drawn from preparations made from dried material) . 
