Retrograde Varieties 135 



Burbank of Santa Rosa, California, is also a 

 very curious variety, the kernel of which is fully 

 developed but naked, no hard substance inter- 

 vening between it and the pulp. 



More curious still are the unbranched varie- 

 ties consisting of a single stem, as may be seen 

 sometimes in the corn or maize and in the fir. 

 Fir-trees of some three or four meters in height 

 without a single branch, wholly naked and bear- 

 ing leaves only on the shoots of the last year's 

 growth at the apex of the tree, may be seen. Of 

 course they cannot bear seed, and so it is with 

 the sterile maize, which never produces any 

 seed-spikes or staminate flowers. Other seed- 

 less varieties can be propagated by buds ; their 

 origin is in most cases unknown, and we are not 

 sure as to whether they should be classified with 

 the constant or with the inconstant varieties. 



A very curious loss is that of starch in the 

 grains of the sugar-corn and the sugar-peas. 

 It is replaced by sugar or some allied substance 

 (dextrine). Equally remarkable is the loss of 

 the runners in the so-called '' Gaillon " straw- 

 berries. 



Among trees the pendulous or weeping, and 

 the broomlike or fastigiate forms are very 

 marked varieties, which occur in species belong- 

 ing to quite different orders. The ash, the 

 beach, some willows, many other trees and some 



