X INTRODUCTION. 



Among regular flowers of many petals, the only form 

 which, it will be necessary to mention here is the cruci- 

 form, consisting of four petals placed cross-wise, as in 

 the Cruciferous Tribe, p. 36. 



The most remarkable among the irregular, is the 

 papilionaceous, (from papilio, a butterfly,) consisting of 

 five petals, of which the upper one, called the standard, 

 is usually the largest ; the two side ones are termed 

 wings, and the two lower ones, which are often com- 

 bined, form the keel, p. 139. 



Both calyx and corolla are not always found in the 

 same flower, and when one only is present, it is some- 

 times difficult to decide by what name it should be 

 called. In this case the term perianth (from the Greek 

 peri, around, and anthos, a flower) is a convenient one. 

 Some flowers have neither calyx nor corolla, as Water 

 Star- wort, p. 558. When the perianth is said to be 

 double, it is to be understood that calyx and corolla are 

 both present. 



THE STAMENS. Within the perianth, and frequently 

 attached to it, is a row of delicate organs called stamens, 

 of which the lower part is termed thejila- 

 ment, the upper the anther. When the 

 filament is slender throughout, it is said 

 to be thread-like; but if it be thick at 

 the base, and taper to a point, it is said 

 to be awl-shaped. The anther varies in 

 shape, but is most frequently oblong, 

 and composed of two lobes and as many cells, which 

 are filled with a fine dust, called pollen. If there 

 be no filament/ the anther is said to be sessile. In* 

 a majority of flowers the number of stamens equals that 

 of the petals ; a few plants have but one stamen : very 

 often the number of stamens is some multiple of the 

 petals, that is, there are twice or thrice, &c. as many, 

 and not a few flowers have from twenty to several 

 hundred. Sometimes the filaments are united at the 

 base into one or more sets, as in Hypericum, p. 117; 



