282 VEGETABLE ORGANOGRAPHY. 



posita? and some Dipsaceas, may be considered either 

 as the hairs of pappi united together, or as membranes 

 formed by a greater abortion of the limb of the calyx 

 than ordinary. 



The second class of scales are the expansions peculiar 

 to certain organs ; thus, the calyx of Salsola bears-upon 

 its back membranous appendages which form part of 

 that organ, the throat of Nerium Oleander, Silene, &c. 

 is prolonged into petaloid scales which collectively form 

 a kind of crown ; these different bodies, whatever their 

 origin, are not special organs, but simple forms peculiar 

 to such or such a part. 



Lastly, the most frequent sense of the word scale is 

 to designate small fiat bodies which are the rudiments of 

 abortive leaves or analogous organs, such as stipules, 

 bracts, or sepals, or even of the other floral organs 

 reduced to very small dimensions. This degeneration 

 changes their form and appearance, and causes them not 

 to be recognised by those who are not acquainted with 

 this kind of change. Examples taken from the different 

 organs will suffice, I think, to make me understood. 



It is customary to say, that the calyces of Pinks are 

 furnished with four scales at their base ; but whoever 

 will examine them with care, will perceive that they are 

 only the upper leaves or bracts, which from being near 

 the flowers, remain very small, and have taken the 

 appearance designated in other cases by the term scales. 



The branches of most of the Erythroxyleas, of 

 Pictetia squamata, and several other plants, are often 

 invested with little imbricated and scarious scales, which 

 are persistent and very close stipules, the leaves of 

 which are wanting. 



The bracts which form the involucra of the flowers 

 of the Compositae and Dipsaceas are leaves reduced to 

 small dimensions, and for this reason have received the 



