188 REV. PROF. G. HENSLOW ON THE 
become connected by a sclerenchymatous ring or cylinder, very 
loosely conneeted with lax mesophyll or merenchyma to the two 
epidermides. This ring consists of two or three layers of cells 
only. After supplying the corolla (3, p) the central cylinder 
becomes pentagonal (3), the posterior lobe representing the 
lost stamen. The remainder now forms six distinct cords, two 
being dorsal carpellary, and four placentary (4). The latter 
coalesce and form ares with their convex sides towards the 
centre (5). As soon as the four cavities are visible, transverse 
arcs of cords are discovered eonnecting each pair of marginal or 
placental cords with their proper dorsal cord (the inner broken 
circle in fig. 6). From these are given off others at right 
angles, in connection with an outer circle of cords. This latter 
ringlies near the base of the disk, and it gives off vertical 
branches running upwards towards the lobed margin of the disk 
(7. Hence the disk is supplied with cords quite unlike the vast 
majority of honey-secreting glandular structures ; and the forma- 
tion is similar both to the origin of the cords in the corolla of 
Jasione, of the stamens of Hypocheris, and of stipules generally. 
XLV. STACHYS PALUSTRIS and S. sYLYATICA differ from the 
preceding in supplying the corolla, stamens, and carpels simul- 
taneously (1). In this section the ten cords for the sepals are 
visible on the circumference (1, s.), and the five petaline (p-) 
four staminal (s¢.), two dorsal cords (d.e.), and two placental (pl.) 
are all visible at once. The last-named soon separate into four 
distinct batches of tracheæ. Figure 3 shows the first appearance 
of the ovary-cells surrounded by the thick disk (D), which is 
supplied with cords as in Lamium. A vertical section (2) shows 
plainly how these arise, pass into the deeper part of the disk, 
then contract again and pass upwards into the ovary; so that 
the plexus seen in the gland ina transverse section is simply due 
to an expansion of the dorsal cords or similar branches from the 
marginal cords ( Lamium, xuty. 6, Z): 
XLVI. BALLOTA NiGRA.— The pedicel supplies ten cords to the 
sepals (1, s.) and five for the petals of the corolla (1, p.) ; but instead 
of then giving off the staminal cords before the carpellary, these 
two whorls are supplied simultaneously; so that a cross section 
reveals two isolated cords (d.c.) forming the posterior and anterior 
dorsal cords, with two slightly crescent-shaped massive cords (2); 
and it is these which supply the four stamens as well as the 
marginal or placentary cords. 
