238 



ORGANOGRAPHY. 



Avhich exhibit this curious departure from their ordinary growth. 

 In the Monkshood (Aconitum) (fig. 482) the two petals which 

 are situated under the helmet-shaped sepals already noticed (fig. 

 442), are each shaped somewhat like a curved horn placed on a 

 long channelled stalk. 



The corolla is usually composed of but one whorl of petals, and 

 it is then termed simple, but in some flowers there are two or more 

 whorls, as in the White Water- Lily (fig. 438), in which case it is 

 multiple. When the corolla is composed of but one whorl, its 

 parts in a regular arrangement alternate with the sepals, al- 

 though cases occur in which tfiey are opposite to them. The 

 reason of this will be explained hereafter, under the head of the 

 General Morphology and Symmetry of the Flower. 



On the inner surface of the petals of many flowers, we may fre- 

 quently observe appendages of difi'erent kinds in the form of scales 

 or hair-like processes of various natures. These are commonly 

 situated at the junction of the claw and limb, or at the base of 

 the petals, as in Mignonette (Reseda) (fig. 484), Ranunculus (fig. 

 483), Lychnis (fig. 486), Parnassia (fig. 485), &c. Similar 



Fig. 483. 



Fig. 484. 



Fig. 485. 



Fig. 483. Tetal of Crowfoot with a nectariferous 

 scale at its base. Fig. 484. One of tlie pe- 

 tals of Mignonette (.Reseda) Fig. 48.5. A 



petal of tlie Grass of Parnassus {Parnassia pa- 

 lustris) bearing a fringed scale. 



scales may be also frequently noticed in monopetalous corollas 

 near the throat (fig. 468), as in many Boragineous plants, for 

 instance theComfrey, Borage, Forget-me-not (fig. 468, r), also 

 in the Dodder, &c. 



Sometimes these scales become more or less coherent and 

 form a cup-shaped process, as in Narcissus (fig. 487), to this 

 the term corona is commonly applied, and the corolla is then 

 said to be crowned. By many botanists, however, this term is 

 applied, wlicncvcr the scales or appendages are arranged in the 

 form of a ring on the inside of the corolla, whether united or 

 not. The beautiful fringes on the corolla of the Passion-flower 

 are of a similar nature. The origin of tliese scales is by no 

 means clearly ascertained ; by some botanists, they are supposed 

 to be derived from the petals, by others, to be abortive stamens; 



