162 REV. PROF. G. HENSLOW ON THE 
The two pairs of small cords in front of the lateral stamens 
(vir. 7) might be regarded also as two abortive placental cords. 
This is countenanced by the fact that in Tetrapoma a stigma arises 
over the summit of them, just as two extra stigmas are borne by 
the pistil of Eschscholtzia. The function of these lateral cords is 
now altered for the simple purpose of nourishing the valves, just 
as the extra cords between the placentas do the same in Poppies. 
The result is that while the, so to say, “valvular carpels ” of 
| the Crucifere are broad and devoid of placentas and stigmas, the 
‘others which bear the placentas are narrow, and the dehiscence 
between the carpels takes place along the lines of marginal 
sutures. 
FREE FORMATION or TRACHEIDS, 
The system of cords formed in the wall of the ovary of Poppies, 
alternating with the placentas, originates quite freely from meri- 
stematic tissue embedded within the parenchyma. They have no 
connection with any cords arising from the axis from below. 
After supplying the stamens (v.5; PL XXIIT) nothing but the 
placental cords exist (v. 6), and the elaborately ramifying cords 
which subsequently appear (figs. 7, 8) arise quite independently 
within the wall and brauch upwards and laterally as well as hori- 
zontally towards the central ovarian cavity (fig. 8). 
The only other instance known to me of a group of tracheids 
originating freely, is a pair of star-like clusters between the 
ovarian cords in the Boragineæ (xıvı1. and xvIII. ; Pl. XXX.). 
Honey-secreting GLANDS AND Disks. 
These may be formed anywhere. All the floral organs are 
capable of giving rise to them, though the floral receptacle and 
receptacular tube probably furnish the greater number. In no 
case have they any vascular structure strictly speaking proper to 
them, as is the case with foliar organs. With rare exceptions, they 
consist of modified epidermal and hypodermal tissue with not even 
any associated cords of neighbouring organs. In the male flowers 
of Lychnis dioica (xir. 8, 9; Pl. XX V.) and Buxus sempervirens 
(111.9; P]. XXXI.) the nectary occupies the position of the pistil, 
but the vascular system belonging to that organ is atrophied and 
only reaches the base of the secretive tissue. In the Labiate 
(XLIV. 6, xv. 2; Pl. XXX.) the dorsal-carpellary cord spreads 
out and forms a network behind the disk or gland, but contracts 
