164 
ON PLANTS IN RELATION TO ANIMALS. 
A few terms specially made use of in describing plants of 
this family may require some explanation. 
The calyx is said to be bisaccate when two of the sepals a 
little outside the two others, are broader at the base, forming 
little protuberances or pouches. The pod is termed a siliqua 
or siliquose when linear, at least three or four times as long 
as broad; and a lomentum or lomentose when it does not 
open in valves. 
The nerves on the pod, often used as a generic character, 
can be best seen on dried specimens; they are even some¬ 
times quite imperceptible on the fresh pod. The seeds are 
said to be in one row when, from thp narrowness of the pod 
or the length of the seed-stalk, they occupy the centre of 
the cell, the two rows being, as it were, blended into one, or 
in two rows , when the two rows are distinct without over¬ 
lapping each other. 
In the embryo, the radicle is said to be accumbent when 
it is bent down on the edge of the cotyledons, incumbent 
when bent over the back of one of them; in the latter case 
the cotyledons are either flat or conduplicate , that is, folded 
longitudinally over the radicle. 
It must be admitted, however, that, notwithstanding all 
these nice distinctions, the genera of Crucifers , as at present 
defined, are often as artificial as they are difficult. 
Different authors divide the Crucifera into various groups 
but for our purpose it will be sufficient to adopt the old 
Linniean divisions of Siliquosa —long-podded and Siliqulosci 
—with a short pod or a pouch. Of course the order in this 
system would be tetradynamia in reference to the arrange¬ 
ment of the stamens but we prefer the term Cruciferse or 
cross bearers. 
Upon these plants then we shall for the present confine 
our remarks to the following. 
Genus —BRASSICA = Cabbage Tribe. 
“Fruit a siliqua, usually four times as long as broad, 
sub-cylindrical or linear (except in some of the species of 
Nasturtium), not divided by transverse partitions, opening 
when ripe by two valves, which split away from the 
replum.”* 
It is now the custom to unite the mustards and cabbage 
in the same genus, adopting the plan of sub-genera thus: 
Sub-genus I.—SINAPIS Linn. 
Sepals spreading, glabrous. Seeds sub-globular, arranged 
in a single row down the middle of each cell of the pod. 
* Sowerby’s ‘English Botany,’ new edition, vol. i, p. 123. 
