GROSSITLARIACE^ 319 



ceptacle and leading to the sepals, petals and stamens, the 

 inner to the carpels. Thus it is seen that a large portion of 

 the flesh of the Ribes fruit is toral and not carpellary. 

 Toral or receptacle tissue and carpellary tissue imperceptibly 

 grade into each other. 



Seeds. — The seeds are small, and slightly flattened on one 

 side. The outer layer of the seed coat is comparatively thick 

 and gelatinous and the inner layer is thin. There is an 

 abundance of endosperm. A minute embryo occurs at the 

 base of the seed. 



Geographical. — There are about 100 species of the genus Ribes. These are, 

 for the most part, natives of temperate Europe, Asia, North America and the 

 Andes of South America. 



Key to Important Species of Genus Ribes 



Stems with one to three thorns below the clusters of leaves, often with nu- 

 merous scattered prickles on the branches, sometimes upon the fruit 

 also. Leaves plaited in the bud (Fig. loi) (Gooseberries). 

 Fruit unarmed and smooth; spines on the branches generally solitary 

 (sometimes triple) and slender. R. oxyacanihoides (common gooseberry) . 

 Fruit armed with prickles, or rough and glandular-hairy; spines on the 

 branches usually three together, stout. R. grossularia (European 

 gooseberry). 

 Thornless and prickleless; leaves plaited in bud (Fig. loi); racemes few- to 

 many-flowered (Currants). 

 Torus dilated immediately above the ovary. 

 Leaves without resinous-dots beneath; fruit red or light. R. rubrum 



(garden currant). 

 Leaves with resinous dots beneath; fruit black. jR. nigrum (Euro- 

 pean black currant). 

 Torus prolonged above the ovary into a campanulate, cylindrical 

 tube. R. americanum (American black currant). 

 Thornless and prickleless; leaves convolute in the bud (Fig. lor); racemes 

 several flowered; torus above much elongated, bright yellow. R. aureum 

 (Missouri, flowering, golden, or Buffalo currant). 



