EXPERIMENTAL EVOLUTION AMONGST PLANTS. 95^ 



notice, although, at the same momeut, they are hoping for the 

 time when they shall see the origination of a new species of 

 plant ! But this curious bean evolution has not stopped here. 

 The old Scarlet Runner and White Dutch Runner of our gardens 

 {Phaseolus multijlorns) have well marked botanical characters in 

 the leaves, inflorescence, pods, beans, and particularly in the 

 roots, which are fleshy and perennial, and in the very tall twining 

 habit. Yet, at the moment when dwarf forms had sprung off the 

 Lima stock — in the same way as the common bush beans 

 undoubtedly had sprung off the stock of the common pole bean 

 before Linnjfius's time — a bush beau sprung off the stock of the 

 old White Dutch Runner, and this is known in commerce as 

 Barteldes's Bush Lima. But this singular bean has other charac- 

 ters than the very dwarf complete bush habit, to distinguish it 

 from its parent, for it differs in a smaller inflorescence, in foliage, 

 and particularly in a remarkable tendency towards a fibrous annual 

 root. Here is a new form Avhich surely ought to satisfy any 

 person who demands the direct origination of a new species, as a 

 proof of evolution. 



There are other curiosities amongst the beans. Gardeners 

 know two well-marked types or races of the Lima bean, the Sieva 

 type and the Large Lima type. There are good and valid 

 botanical distinctions between the two, which were amply recog- 

 nized by Linnieus, who, supposing that one came from Bengal 

 and the other from Africa, made species of them. The smaller, 

 or what we now know as the Sieva type, he called Phaseolns 

 lunatus; the other he called P. inamomus. The term Lima bean, 

 which all agree in associating with Phaseolus lunatus, should 

 properly be applied, therefore, to the Sieva type. For a century 

 these species of Linnaeus were generally considered to be good, — 

 that is, distinct and valid. It is now pretty well established that 

 both these beans came from Brazil. Only one of them is known 

 in a truly wild state, and the suspicion is so strong, therefore, 

 that the other sprung off from it under cultivation, that the two 

 types are now united as one species. Still a third well-marked 

 type, differing in shape and texture of leaflets, and characters of 

 pods and seeds, has now originated from the Large Lima type ; 

 this is the Potato Lima type. It should also be said that Macfad- 

 yen, in his flora of Jamaica, made four new species out of the 

 Lima type of beans. Here, then, are three groups of beans, each 



