CLASS XV. 
TETRADYNAMIA* 
SILICULOSA. 
(1) Pouch not notched at the end. 
ALYS'SUM. Pouch egg-shaped, crowned with the style: 
valves concave : Filaments toothed : ( Cotyledons accum- 
bent. Br. E.) + 
(CAMELI'NA. Pouch entire ; valves tumid: Seeds numerous, 
not bordered: Filaments without teeth: Cotyledons in¬ 
cumbent. Br. E.) 
DRA'BA. Pouch with nearly flat valves : Style none : (Coty¬ 
ledons accumbent. Br. E.) 
* (The importance of the plants of the natural order of Cruciferce to mankind, and the 
highly antiscorbutic powers of which they are possessed, have been indicated in our first 
volume. This latter quality appears to depend upon a certain acrid volatile oily principle, 
the chemical nature of which is imperfectly known ; and it is observed that when any 
cruciferous plants are found to be eatable, either from culture or other circumstances, 
the improvement arises from a reduction of this peculiar principle. Plants of this order 
are also believed to possess diuretic and diaphoretic properties. Cruciferce are always 
eatable when their texture is succulent, as in the roots of the Radish and Turnip, and in 
the leaves of the Cabbage tribe. A further diminution of the acrid principle is produced 
by blanching. These vegetables are supposed to possess a greater share of azote than any 
others ; which occasions their fetid smell when fermented. The embryos of all the order 
abound in oil, whence many species are employed with much advantage for expressing, 
either for the table, or for supplying lamps. Some are extremely beautiful and fragrant; 
and others among the most interesting of alpine plants. The more common kinds are 
of considerable utility to bees, as affording them a principal supply of spring food. 
They are also much frequented by different White Butterflies, as Pontia Brassicce , Cha- 
riclea , Rapes, metra, Napi, Sfc. well described and figured in Mag. Nat. Hist. vol. ii. p. 22 7* 
It is asserted that the seeds of cruciform plants, as also grain of all kinds, by steeping 
twelve hours in river water, (never in well-water,) and adding to each quart of water about 
fifteen drops of a strong solution of chlorine, the whole well mixed, and the maceration of 
the seed continued for six hours longer in the sun-light, and under a bell-glass, will be 
much increased in vegetative power, and, with the water of maceration poured over the 
ground when sown, will produce a crop three or four times as great as that obtained 
under ordinary circumstances ; a fact worthy the attention of the agriculturist in seasons 
of scarcity, or when the seed may have suffered from depredation. Vid* Mag. Nat. 
Hist. E.) 
+ (The circumstance of the pouch being notched at the end, or otherwise, affords no- 
certain characteristic of this genus. E.) 
