ORGANOGRAPHY AND GLOSSOLOGY. 



41 



(6), or fasciculate (c) appearance, as in many of the 

 Orchidese. All these swollen portions serve as reser- 



voirs of nutriment for the future use of the plant, but 

 they should not be confounded with certain analogous 

 modifications of the underground portions of stems, 

 which we shall describe when we speak of the real 

 " tuber." 



The extremities of some aerial roots, as in the Panda- 

 nus, are coated by exfoliations of the epidermis ; and 

 the same may be observed on those of the hyacinth. 

 The little Lemnce, or duckweeds (fig. 31. 6), whose roots 

 hang suspended in the 

 water, have a distinct 

 cup-like appendage at- 

 tached to their extremi- 

 ties. In the early state 

 of their development this 

 formed a membranous 

 sheath (a), which com- 

 pletely enveloped them, 

 but which became rup- 

 tured at the base as they elongated, and was then carried 

 downwards as they continued to grow. 



(42.) Bladders. The roots of certains aquatics be- 

 longing to the genus Utricularia, are furnished with ap- 

 pendages, in the form of little membranous bladders 



