246 BOTANY OF CROP PLANTS 



is a globose berry with two seeds (sometimes more), in each 

 of the three locules. The seeds are subglobose, often dark in 

 color. The embryo is cylindrical. 



Economic Importance of Genus. — The genus Asparagus 

 contains about 150 species distributed throughout tem- 

 perate and tropical parts of the Old World. There are 

 numerous ornamental species, the most common being 

 Asparagus medeoloides (smilax), A. plumosus (the plumy 

 asparagus), a cUmbing plant used for decorative purposes 

 and often called "asparagus fern," and A. sprengeri, another 

 "asparagus fern," much used for planting in hanging baskets. 

 The only edible species of any consequence is Asparagus 

 officinalis, the common garden asparagus. 



ASPARAGUS OFFICINALIS (Asparagus) 



The common garden asparagus is a much-branched peren- 

 nial herb reaching a height of 3 to 7 feet. 



Roots. — The roots (Fig. 99) are numerous and fleshy, ex- 

 tending horizontally in the soil to some distance, but being 

 confined to the surface layers. They arise both from the 

 sides and bottom of the thickened rootstock. Each year new 

 roots are produced and the older ones die and become hollow, 

 without becoming separated from the stem. New roots ap- 

 pear above the older, which accounts for the so-called 

 "lifting" of the plants. 



Stems. — ^Asparagus bears both subterranean and aerial 

 stems. The underground stems are rootstocks. They are 

 much thickened, branched, rather woody, and about as long 

 as broad. The rootstock or " crown " makes an annual growth 

 of I to 3 inches. Its extension is horizontal, taking place at 

 one or both ends. The older portions of the rootstock gradu- 

 ally die. The rootstocks send up aerial shoots (Fig. 99). 

 These at first are thick and fleshy ("spears") and form the 



