OUTLINES OF BOTANY, XXV 



93. Thus, a Flower is 



disepalous, trisepalous, tetrasepalous, polysepalous, etc., according as there 

 are 2, 3, 4, or many (or an indefinite number of) sepals. 



dipetalous, tripetalous, polyp etalous, etc., according as there are 2, 3, or 

 many petals. 



diandrous, triandrous, polyandrous, etc., according as there are 2, 3, or 

 many stamens. 



digy notes, trigynous, polygynous, etc., according as there are 2, 3, or many 

 carpels. 



And generally (if symmetrical), dimerous, trimerous, polymerous, etc., ac- 

 cording as they are 2, 3, or many (or an indefinite number of) parts to each 

 whorl. 



94. Flowers are unsymmetrical or anisomerous, strictly speaking, when any 

 one of the whorls has a different number of parts from any other ; but when 

 the pistils alone are reduced in number, the flower is still frequently called 

 symmetrical or isomerous, if the calyx, corolla, and stamina] whorls have all the 

 same number of parts. 



95. Flowers are irregular when the parts of any one of the whorls are un- 

 equal in size, dissimilar in shape, or do not spread regularly round the axis at 

 equal distances. It is however more especially irregularity of the corolla that 

 is referred to in descriptions. A slight inequality in size or direction in the 

 other whorls does not prevent the flower being classed as regular, if the corolla 

 or perianth is conspicuous and regular. 



§ 9. The Calyx and Corolla, or Perianth. 



96. The Calyx (90) is usually green, and smaller than the corolla ; some- 

 times very minute, rudimentary, or wanting, sometimes very indistinctly whorled, 

 or not whorled at all, or in two whorls, or composed of a large number of 

 sepals, of which the outer ones pass gradually into bracts, and the inner ones 

 into petals. 



97. The Corolla (90) is usually coloured, and of a more delicate texture 

 than the calyx, and, in popular language, is often more specially meant by the 

 flower. Its petals are more rarely in two whorls, or indefinite in number, and 

 the whorl more rarely broken than in the case of the calyx, at least when the 

 plant is in a natural state. Double flotvers are in most cases an accidental de- 

 formity or monster in which the ordinary number of petals is multiplied by the 

 conversion of stamens, sepals, or even carpels into petals, by the division of 

 ordinary petals, or simply by the addition of supernumerary ones. Petals are 

 also sometimes very small, rudimentary, or entirely deficient. 



98. In very many cases, a so-called simple perianth (15) (of which the parts 

 are usually called leaves or segments) is one in which the sepals and petals are 

 similar in form and texture, and present apparently a single whorl. But if 

 examined in the young bud, one-half of the parts will generally be found to be 

 placed outside the other half, and there will frequently be some slight difference 

 in texture, size, and colour, indicating to the close observer the presence of both 

 calyx and corolla. Hence much discrepancy in descriptive works. Where one 

 botanist describes a simple perianth of six segments, another will speak of a 

 double perianth of three sepals and three petals. 



99. The following terms and prefixes, expressive of the modifications of 

 form and arrangement of the corolla and its petals, are equally applicable to the 

 calyx and its sepals, and to the simple perianth and its segments. 



100. The Corolla is said to be monopetalous when the petals are united, 

 either entirely or at the base only, into a cup, tube, or ring ; polypetalous when 

 they are all free from the base. These expressions, established by a long usage, 

 are not strictly correct, for monopetalous (consisting of a single petal) should 



