Actinostemma biglandulosa. 645 
pletely by phloem, as occurs in the primary bundles. Pri¬ 
mary and secondary bundles are connected at intervals by 
anastomoses which traverse obliquely the medullary rays. 
My thanks are due to the Regius Keeper of the Royal 
Botanic Garden, Edinburgh, who kindly supplied the materials 
for this work, which, moreover, was done at the Laboratory 
of the Garden, under his supervision. 
EXPLANATION OF FIGURES IN PLATE XXXIV. 
Illustrating Mr. Wallace’s Paper on Actinostemma. 
Fig. 1. Diagrammatic transverse section of a young internode, showing the 
arrangement and roughly the proportions of the vascular bundles. Xylem light, 
phloem dark. 
Figs. 2, 3, 4. Diagrammatic transverse sections of stem at successively lower 
levels, illustrating the growth and differentiation of the various bundles. 
Fig. 5. Diagrammatic transverse section of old hypocotyl, showing accessory 
bundles, of which there is one opposite each primary bundle. Shading as before : 
sclerenchyma brown. 
Fig. 6. Portion of a transverse section of hypocotyl of seedling, showing one of 
four bundles. E — starch-sheath or endodermis. The cells immediately within 
the starch-containing cells will become sclerenchyma. The circular dots are starch 
grains, x 90. 
Fig. 7. Portion of transverse section of stem of seedling, showing one of the 
three larger inner bundles in the primary condition, ph — phloem,/# = proto- 
xylem, cb — cambium, P — fundamental tissue, x 350. 
Fig. 8. Portion of a transverse section of hypocotyl of seedling, showing the inner 
face of one of the six bundles, px = protoxylem, P = fundamental tissue, x 350. 
Fig. 9. Portion of a transverse section of an internode about one-eighth inch in 
diameter, showing the small-celled meristem on the inner face of the wood of one 
of the three large inner bundles, px = protoxylem, m = meristem, P = funda¬ 
mental tissue, x 350. 
Fig. 10. Portion of a transverse section of older hypocotyl, showing inner face 
of one of the six bundles, px = protoxylem, ph = phloem, m. c. — medullary 
cambium, x 350. 
Fig. 11. Portion of a transverse section of stem a short distance above the 
insertion of the cotyledons, showing division of cells of the endodermis to form 
the meristem in which accessory bundles arise, s = sclerenchyma, E — endo¬ 
dermis. x 350. 
Fig. 12. Portion of a transverse section of older stem above the insertion of the 
cotyledons, but at a lower level than the section of which Fig. 11 represents a 
portion; it shows the new bundles in the endodermis. x = xylem, ph = phloem, 
c = cambium, m — medullary ray : all formed from the endodermis. s — scleren¬ 
chyma, ph — the position of the phloem of two primary bundles, MR — medul¬ 
lary ray between them, x 90. 
