The Citrous Fruits. 101 



2. Practice grafting the above-named fruits, so far as 

 means and the time of 3'ear permit. 



3. Study the trees of the above-named fruits until each 

 species can be recognized at a glance. This study may be 

 made at any time of the year. 



4. Practice picking and packing the fruits of the differ- 

 ent species, so far as the season permits. 



5. Practice naming standard varieties of fruit from the 

 descriptions in Downing's " Fruits and Fruit Trees of 

 America." 



6. Practice writing descriptions of mature samples of 

 standard varieties of fruits. 



T. Begin a collection of pits of the different varieties of 

 the stone fruits, to be used later for determining varie- 

 ties. Number each pit, and catalogue the varieties by 

 number. 



Section Jf.. — The Citrous Fruits 



131. The principal citrous fruits grown commercially 

 in the United States for their fruit are the following: 



(a) The sweet orange {Citrus aurantiitm, variety Sinen- 

 sis). 



(b) The mandarin or kid-glove orange {Citrus nobilis). 



(c) The lemon {Citrus medica, var. Limon). 



(d) The lime {Citrus medica, var. acida). 



(e) The pomelo {Citrus Decumana). 



All are small trees or shrubs with evergreen leaves, and 

 are hardy only in the extreme south or southwest. The 

 fruit of all the above species is injured, while on the tree, 

 by a temperature slightly below the freezing point, and 

 the younger branches of the trees are destroyed by moder- 

 ate freezing. 



