56 SWEET PEAS 



any one variety is worth saving. The accompanying illustrations 

 and explanations should serve to elucidate any points not already 

 made clear. 



A Simple Exposition of the Meiidelian Theory in 

 Cross-Breeding. In view of the widespread interest taken 

 in Mendel's theory relative to the cross-breeding of plants, a few 

 elementary observations may be welcomed by raisers, or would-be 

 raisers, of new Sweet Peas. To follow out Mendel's laws to any 

 extent is an exceedingly intricate study, for it leads to a multiplicity 

 of confusing equations that are calculated to repel rather than to 

 assist the student. 



Mendel and His Experiments. Before considering the 

 application of Mendel's laws it may not be out of place to take a 

 passing view of Mendel himself. George Johann Mendel was a 

 priest in an Augustinian foundation at Alt-Briinn. In 1851 he 

 moved to Vienna and spent four years there studying physics and 

 natural science. From the report of the Royal Horticultural 



FIG. 7. CROSS-FEBTILISATION OF THE SWEET PEA 



Z, external parts of flower or parts of corolla : k, vexillum or standard ; 

 i, alee, or wings ; j, carina, or keel. A, other parts of blossom : 

 k, calyx, composed of leaves called sepals ; I, stamens, ten in number, 

 nine of them being joined into a tube by their jila ments or stalks, the 

 remaining one is free ; m, pistil, consisting of a solitary carpel, which 

 even at this early stage is seen to be a young pod, inside which are the 

 ovules, destined to become seeds ; n, anthers of stamens by which 

 pollen or fertilising " dust " is carried ; o, stigma of pistil or receptive 

 organ. 



B, flowering stem : p, flower at stage when usually self -fertilisation has 



been effected ; q, blossom at stage when emasculation (removal of 

 anthers of stamens), must be effected, the wings being held open by 

 Chrysanthemum flower-dressing tweezers, and the keel depressed by a 

 needle; the anthers are removed from the flower before pollen cases 

 burst ; r, wings ; s, keel. 



C, flower before emasculation (shown in section for clearness) : t, sepals ; 



u, standard ; v, wing ; m, keel ; x, carpel or pod ; y, stamens from 

 which anthers are to be cut off. 



D, emasculated flower (in section) : z, feathered stigma to which pollen of 



desired variety is to be applied liberally by means of a camel-hair 

 brush. 



E, result of effective pollination and fertilisation : a t pod open ; b, seeds. 



