68 A NEW TYPE OF MEDULLOSEA FROM THE LOWER COAL-MEASURES. 
Fig.13. Longitudinal section from primary wood of stele, to show the xylem-parenchyma, which 
| contains secretory sacs. From a section of Prof. Oliver's, University College, London, 
0.36 C. x about 60. | 
Fig. 14. Transverse section of a radially symmetrical bundle from a leaf-base. Note the parenchyma 
| in the xylem and the large phloem-elements, s.£. ; J.S., fibrous strands. From Section XIII. 
x about 40. 
Fig. 15. Transverse section of a unilateral bundle from a leaf-base. pæ., protoxylem ; s.t., large elements 
En of the phloem. From Section XIII. x about 50. 
Fig. 16. Transverse section of part of a leaf-base. Ay., hypoderma ; v.b., vascular bundles, with 
os sclerotic strands surrounding them. From Section X. The part figured here will be found 
on the lower side of fig. 5, to the left. x about 6. 
Fig. 17. Transverse section of part of a petiole from Colne, showing hypoderma, vascular bundles, and 
sclerotic strands, to compare with fig. 16. From a section received from Mr. Peter Whalley. 
x about 8. 
Piste I0. 
Drawings by Mr. John Allen. . 
Fig. 18. Longitudinal section of a radially symmetrical bundle from a leaf-base (similar to that shown 
. . in fig. 14, in transverse section). ph., phloem ; pæ., protoxylem, succeeded to the left by 
more densely spiral tracheides, and then by the large pitted elements and parenchyma that 
constitute the xylem. The bundle is not: quite complete on the left. From Section C. 
OE x about 80. 
Fig. 19. Transverse section from the exterior of the large meristele, shown in fig. l. The edge of the 
wood is seen above. st., probable strand of sieve-tubes ;_ $.c., one of the secretory canals, of 
which three are seen in a row in the pericycle. The phloem passes over insensibly into the 
pericycle. From Section IV. x about 55. 
Fig. 20. Nearly tangential section through the phloem of the meristele. The wood lies immediately to 
the right. s.t., branching strand of narrow elements, no doubt including the sieve-tubes j 
s.c., secretory canals. From Section I. x about 60. 
Fig. 21. Radial section through the ‘outer part of the stele, where secondary growth is going 0? 
tr., secondary tracheide, with delicate pit-borders;. ph., secondary phloem; m... tw 
medullary rays, crossing the secondary xylem and phloem, and abutting on the parenchym: 
" of the xylem and pericycle. From one of Prof. Oliver's sections, University College 
ui London, O. 36 b. x about 100. | EI 
Fig. 292. Transverse section of a vascular bundle in a petiole from Shore. pæ. protoxylem ; $-t., larg 
.  phloem-elements, which form a ring round the xylem ; f.s., sclerotic strands accompanyib 
the bundle.. Section 5.. x about 30. 
