22 



THE FLOWER GROWER'S GUIDE. 



In cucumbers and melons, castor-oil plants, begonias, and some others, the male 

 and female organs are borne in separate flowers on the same plant, and such plants 

 are called monoecious or unisexual flowers. 



Then again, we have plants like hemp, hops, nepenthes, and the common aucuba, 

 that bear male flowers or stamens on one plant, and -seed-bearing pistils or ovaries on 

 another individual plant, and such are called dioecious plants. 



Of the four whorls or rows of organs in an ordinary flower, note that the calyx is 

 protective, and the corolla or petaloid-whorl is attractive, then the third whorl of 

 stamens is masculine, and the ovary or seed-vessel is feminine. 



In order for a plant to bear fertile seeds, it is necessary that the pollen should fall or be 

 placed on the stigma at the right time, and in nature this is done either by the wind, or by 

 the bees, flics, or moths, -which flit from one flower to another for nectar, honey, or pollen. 



All the fir-trees, or conifertc, and all the cereals, or corn plants or grasses, are 

 wind-fertilised (anemophilous). On the other hand, many daisy-flowered composites, 

 indeed nearly all gamopetalous genera, are fertilised by insects (entomopliilous), as also 

 arc the orchids and asclepiads, which have their pollen glued together into heavy waxy 

 masses, and not powdery as in most other flowers. As a rule, in nature, the pollen 

 of one species or kind of plant is blo wn or carried to the stigmas of the same species 

 growing in the vicinity, the result being individuals of the same kind or species. 



Cross Fertilisation. 



Kow and then, however, the pollen of one species finds its way to the stigmas of 

 another species in the vicinity, and then, if seed is produced of the union, the plants 

 are difl'crent to either parent species, and are called hybrids. Darwin long ago pointed 

 out the fact that " Nature abhorred perpetual self-fertilisation," and it is now known 

 that she refreshes or rejuvenates herself or her offspring by cross-fertilisation, or by 

 hybridisation now and then. Nature also abhors perpetual vegetative reproduction, 

 especially so unless occasionally refreshed by changes of soil and climate, hence the 

 necessity for fresh soil or change of seed. 



Man has adopted nature's tactics in the garden, and is continually altering or 

 varying, and very often improving, his vegetable produce by cross-fertilising or 

 hybridising the flowers, fruits, or vegetables he cultivates for use or ornament. 



In crossing or hybridising flowers, all that man can do is to transfer the pollen from 

 the anthers of the selected male parent, and place it upon the stigmas of the plant 



