ORGANIZATION OF THE FOSSIL PLANTS OF THE COAL-MEASURES. 777 
Fig. 22. 
Fig, 23. 
Fig, 24. 
Fig. 25. 
Fig 26. 
Fig. 27. 
Fig. 28. 
inner cortex; sc., sclerotic masses seen in both stem and branch; d.c., 
outer cortex of stem and branch; cy., stele of branch, with commencement 
of secondary wood. x 8. O.N. 1915N (Dulesgate) (see pp. 745 and 758). 
Somewhat oblique, longitudinal section of a stem, showing the bases of 
two petioles, pt. ; the left-hand petiole is seen in nearly radial section. cy., 
stele of stem ; %.¢., inner cortex, which in both petiole and stem is marked 
by the transverse sclerotic bands; d.c., outer, or Dictyoxylon cortex. 
x 24. C.N. 1286 (Burntisland) (see p. 754). 
Fragments of foliage from another section of the same block. Portions 
of petioles, pt., of all sizes, are shown, characterized by the cortical 
structure. At /. are fragments of leaflets; sm.,a fern-sporangium. X 14. 
C.N. 1287 (Burntisland) (see p. 755). 
Part of a transverse section of a stem, showing one of the primary xylem- 
strands at the periphery of the stele. pzx., protoxylem; «., centripetal, 2.', 
centrifugal, part of xylem; mw., metaxylem, which extends through the 
whole interior of the stele; c¢.p., conjunctive parenchyma; «.”, secondary 
wood; cb, cambium; ph.®, secondary phloém. x 200. C.N. 1293 
(Burntisland) (see pp. 748 and 751). 
Radial section through the corresponding region of another stem, to show 
the mesarch structure of the xylem-strand. «.*7., ray belonging to the 
secondary wood. Other lettering as in previous figure. Note the well- 
preserved bordered pits of the centripetal xylem. x 200. C.N. 1266 
(Burntisland) (see pp. 748 and 751). 
PLATE 27. 
Part of a transverse section of a stem, showing a collateral leaf-trace bundle, 
just separating from the stele. px., px., probable position of the protoxylem- 
groups; «., centripetal, «.’, centrifugal, part of xylem of bundle; ph.’, its 
phloém ; x.?, secondary wood of stem ; ph,, phloém ; pe., pericycle ; c., inner 
cortex. X70. O.N. 1253 (Burntisland) (see p. 750). . 
Transverse section of a tetrarch root, probably belonging to H. Grievit. 
px., px., two of the four protoxylem-groups, at the corners of the massive 
primary wood ; «.”, secondary wood; cb., cambium ; ph., phloém ; c.’, inner 
cortex ; ¢.,-outer cortex, or epidermal layer. x 40. C.N. 1915r (Dules- 
gate) (see p. 758). 
Radial section of a stem, bearing three adventitious roots, Rt. rx, xylem 
of root, connected with that of stem; «.’, secondary wood of stem, chiefly 
developed near bases of roots, and partly seen in transverse section; a., 
primary wood of stem ; pe., pericycle ; sc., sclerotic masses, the only remains 
of the cortex. X15. C.N. 1915a (Dulesgate) (see p. 756). 
MDCCCXCV.—B. 5 H 
