NOTES ON SOME HYBRID TUBEROUS SOLANUMS. 



131 



(except those of my * Immune ' [1908] strain, now the property 

 of Messrs. Sutton) were completely destroyed by it. 



In addition to these, among other hybrids of wild types of Potato 

 obtained, the following may be mentioned for comparison with the 

 work of other experimenters : 



1. S. etubeeosum"^^ X S. TUBEROSUM (Mexico). This seedhng has a 

 very strong, erect, dark stem (Nos. 192, 193), the upper parts mottled 

 and green, with wavy edges; the foliage like that of S. tuberomm; 

 leaflets distant upon rhachis, often with several interspersed pairs; 

 terminal leaflets much the largest, edges of leaflets plain (not wavy, 

 as in S. tuberosum). Mower not noted. Berry, much elongated, 

 bronze-green, covered all over with pale whitish-green spots. Tubers 



A 



B 



Fig. 62. — a, Small Berry of Solanum etuberosum x S. tuberosum ; 

 B, Berries of Seedling of S. etuberosum. (Natural size.) 



numerous (forty-six, weighing about 4 oz.), round and flattish round 

 (discoidal), mid-violet colour, smooth (fig. 63, b). Four selfed berries 

 formed, containing 7, 9, 16, and 59 seeds respectively (fig. 62, a). 



2. S. VERRUcosuM X S. ETUBEROSUM."^ This hybrid has a green 

 stem; foliage as in S. verrucosum, but leaflets slightly broader. Flower 

 paler than S. verrucosum and drooping ; style slightly projecting 

 beyond the stamens; calyx large, deltoid-acuminate, not recurved as 



* The Solanum etuberosum used in these experiments (not S. etuberosum 

 Lindl.) is unfortunately a hybrid — presumably a natural hybrid- — so that these 

 two crosses are of less value for tracing the inheritance of characters, and 

 I anticipate that many similar natural hybrids may be found, some of them 

 probably possessing qualities like S. etuberosum which may lead in the future 

 to entirely new strains of potatos. The immense vigour of some of the seedlings 

 of S. etuberosum, is well illustrated by the figures, showing a flower of one 

 and berries of another (figs. 59, a, 62, b). 



K 2 



