June, 1889.] 



THE YOUNG NATURALIST. 



117 



parts of a flower when regular, bear a uniform relation to each other, 

 being equal or double the number, thus with four petals we look for 

 four or eight stamens, and on close inspection there is to be seen the 

 rudiment of an abortive stamen betwixt each long pair. This seems 

 now to have developed the function of a honey-secreting gland to 

 reward the visits of insects, who are attracted by the bright colour 

 and delicious odour of the blossoms. The peculiarly long tube-shaped 

 corolla renders the nectar inaccessible, except to those long-tongued 

 moths whose visits are likely to prove beneficial to the plant. Under 

 cultivation the calyx is often seen to acquire in a considerable degree 

 the hue of the corolla, which aids in making the masses of unexpanded 

 flower buds still more conspicuous. The fruit of the wall-flower is 

 botanically very curious, and is eminently characteristic of the cruci- 

 ferous order. It is formed of two united carpels making a long pod- 

 like fruit, the interior cavity of which is divided by a thin diaphanous 

 membrane, called a replum, and forming a longitudinal partition, so 

 that when the fruit is mature the two outer coverings open at the base, 

 curl up and fall off, leaving the seeds exposed in two rows on each 

 side of the replum, which remains on the stalk a long time after the 

 seeds have been shed. In certain members of the order, such as the 

 honesty (Lunaria biennis), a common plant in cottage gardens, the 

 replum is enormously developed, and when the fruit is well ripened 

 and the seeds dispersed, the replums remain bright and shining like 

 silver shillings, when it forms a useful ornament, like dried grasses for 

 decorative purposes, and like skeleton leaves, becomes a thing of 

 beauty, if not a joy for ever. 



As well as highly ornamental and fragrant flowers like the wall- 

 flower and stock, the cruciferae includes a great number of valuable 

 economic plants, such as the various members of the cabbage family. 

 The. immense number of the varieties of which are descended from 

 the original parent cabbage (Bmssica oleracens) of our rocky sea shores, 

 forms a striking instance of man's power of originating and perpetuat- 

 ing variations by means of judicious cultivation. There are also the 

 turnips, cresses, mustards, rapes, radishes, &c. Many of these are 

 hot and pungent, but none are poisonous, all may be eaten with im- 

 punity, and several are powerful anti-scorbutics and blood purifiers. 

 The old herbalists even credited the wall-flower with being useful for 

 gout and similar diseases, but it has now fallen into disrepute. Poets, 

 however, who are notoriously non-utilitarian, continue to sing its 

 praises. Burns happily indicates its habitat ; — • 



