IS BULLETIN 697, U. S. DEPARTMENT OE AGRICULTURE. 



of lemon. This condition may- be due, in part at least, to the more 

 recent introduction of the Marsh variety and the comparatively 

 small amount of propagation of it, so that only a few bud generations 

 have been available for observation. Recent commercial propaga- 

 tions of this variety have been made, as a rule, with the use of buds 

 selected from trees of the Marsh strain and for the most part by the 

 use of fruit-bearing- buds, which explains the presence of only a small 

 number of trees of the undesirable strains. 



The trees of the Unproductive strain, and the fruits borne by them, 

 are similar to those of the Marsh strain, except that the trees usually 

 bear relatively fewer first-grade valuable fruits and show a marked 

 alternate-season bearing habit. 



INFREQUENT FRUIT VARIATIONS. 



Fruits possessing many minor variations of interest and of some 

 importance have been borne by the performance-record trees in 

 addition to the important strains already described. These varia- 

 tions have not been found as frequently as has been the case in the 

 other citrus varieties in the performance-record plats. Fruits are 

 occasionally found that, from outside appearance, more nearly 

 resemble oranges than grapefruits. Some of these variable fruits 

 resemble in flesh and juice characteristics combinations of some of 

 the qualities of oranges, tangerines, and grapefruits. 



Another variation occasionally met with is the ribbed fruit, an 

 illustration of which is shown in Plate IX. In this case the fruit is 

 usually bell shaped and the peel has regular longitudinal ridges and 

 depressions, giving it a ribbed or fluted appearance. The rind 

 is usually thick, the rag is rather coarse and bitter, the juice is 

 abundant but of inferior flavor and quality, and the fruits are com- 

 mercially seedless. These fruits are probably worthless for com- 

 mercial purposes. 



Fruits having raised or sunken sections, or both, are of rather 

 frequent occurrence, particularly on trees of the Seedy and Rough 

 strains. 



Several fruits having well-developed navels have been found 

 among the fruits on the performance-record trees. In some cases 

 they were absolutely seedless, while in other instances the fruits 

 contained several seeds. So far, no branch or tree has been found 

 bearing only navel grapefruits. No attempt has been made as yet 

 to isolate a strain of navel grapefruits through bud selection, although 

 it seems probable that this can be done. The presence of a navel 

 in the seedless grapefruit, other things being equal, would likely be a 

 disadvantage except as a distinctive mark for the variety. 



Occasional limbs bearing absolutely seedless fruits have been 

 observed in the performance-record trees. Other limbs have been 



