45 2 
Saunders . —Af Reversionary Character 
often showing deep transverse fissures as though the tissues had been torn 
across. Others, though exhibiting no sign of injury, were curved instead of 
straight, or in extreme cases coiled into a spiral like the pods of certain 
Leguminosae. A fuller examination of these Iruits yielded the results set 
forth in the present account. 
2 . Appearance and structure of a typical siliqua in the Stock. 
The chief external feature of the developing Stock siliqua is the outline 
of the valves indicating the place of separation from the replum 1 of the two 
laterally placed carpels when ripe. These outlines are somewhat obscured 
in the hoary type by the dense covering of hairs, but in the glabrous strains 
they are clearly defined, and for this reason these strains offer particularly 
favourable material for the investigation of the points above mentioned. 
The ovary shows the usual two valves. Between them, in the median plane, 
is the somewhat broad tract (commissure) regarded as formed from the con¬ 
joined carpellary edges (Fig. i), the inward extensions of which give rise to 
the placentae, and ultimately become joined at their extremities and so form 
a complete septum. These two intervening tracts can be seen to swell out 
at the top of the siliqua into two large connivent knobs or horns (Fig. 2), 
which may eventually touch (Figs. 5, 6). The valves themselves are defined 
above in the developing fruit by a horizontal ridge (Figs. 3, 7), which may 
merge imperceptibly into the knobs or be delimited from them by a con¬ 
tinuation of one or both of the sutural lines (Fig. 8). Above this ridge the 
two flat surfaces slope backwards (inwards) for a short distance and are 
covered at their summit by the stigmatic papillae. In the young stage the 
commissures are so narrow that the papillae appear to be continuous round 
the dividing cleft, and it may be that the ring is sometimes completed by 
the formation of papillae over the sutures as well as on the valves. But the 
fruits occasionally to be met with, in which the carpels become free from 
each other at the apex (Figs. 9, 10), make it clear that the two main stig¬ 
matic areas are centred over the midrib of each lateral carpel ; that is to say, 
they are not commissural, as is stated to be the arrangement in the Cruciferae 
generally, but alternate with the placentae and replum. As post-fertiliza¬ 
tion development proceeds, the stigmatic bands between the swelling 
terminal knobs become V-shaped, the double V now bordering a shallow, 
bluntly 4-angled, crater-like cavity which may be considered a short stylar 
canal (Fig. 4). Later still this cavity becomes narrowed into a double 
loop or figure of 8 extended crosswise between the pincer-like knobs. Such 
is the outward appearance of normal fruits. 
1 o the internal structure of the siliqua but little attention seems to have 
been paid by earlier observers, beyond notice of the presence or absence of 
1 The term replum is used throughout the present account in its wider sense to include both the 
frame of the placentae and the partition stretching between them. 
