10 INTKODUCTOKY 



Envelopes, which are usually in two series ; the outer of usually green 

 leaves, the Calyx or Flower-cup ; and an inner and more delicate por- 

 tion, the Corolla ; and the Essential Organs, the parts necessary to the 

 production of seed, the Stamens and Pistils, which are also in two series. 

 The portion of the stem to which these are attached is the Receptacle. 

 These parts are arranged on the receptacle in a regular ascending order : 

 first, the calyx ; then the corolla ; within and above this, the stamens ; 

 and in the centre of the flower, the pistils. (Fig. 4.) 



35. The calyx is generally green and leaf-like ; the pieces of which it 

 is composed are called Sepals. 



The corolla is of a more delicate texture than the calyx and of some 

 other color than green ; its parts are called Petals. The broad expanded 

 portion of the petal answering to the blade of the leaf, is its Limb, and 

 the narrowed base, corresponding to the petiole, is, when present, its Claw. 



36. The stamens which are to be found next within the petals have 

 also two parts ; a rounded or lobed body or case called the Anther ; 

 and the usually slender stalk which supports it, the Filament. Although 

 the stamen is so unlike a leaf, the botanist regards it as representing in 

 its anther, the blade of a leaf with its margins infolded to form a hollow 

 bag, and in its filament, the leaf-stalk. This would perhaps be difficult 

 to comprehend if there were not some plants which show a regular gra- 

 dation from green calyx leaves to perfect anthers. In half double roses 

 we can often c-ee bodies that are half petals and half anthers, showing 

 that they are but modifications of the same fundamental organ. As the 

 blade is the essential part of the leaf so is the anther that of the stamen, 

 and the filament may be wanting, when the anther is sessile. The anther 

 produces a powder, usually of a yellow color, which is discharged ordinarily 

 by slits in its walls or sometimes by pores at the apex (Fig. 144) or by 

 valves or trap doors (Fig. 16). The office of this powder, called Pollen, 

 is to fertilize the ovary. Anthers are usually 2-celled, sometimes 4-celled, 

 or one-celled by the confluence or running together of the cells, or by the 

 abortion or disappearance of one of them. 



If the anther rests directly upon the apex of the filament it is innate ; 

 if the whole length of one face is applied to the filament, it is adnate ; 

 when it looks towards the centre of the flower, it is introrse ; when look- 

 ing outwards, extrorse ; it is called versatile when hung to the apex of 

 the filament in such a way as to swing loosely in any direction. 



When the filament is prolonged between the anther-cells it is termed 

 the Connective. 



The number of stamens is expressed by monandrous, diandrous, triaii' 

 drous, &c., for a flower with 1-2 and 3 stamens, &c. ; polyandrous for 

 many stamens : words obtained by putting the names of the classes of 

 Linnaeus, monandria, diandria, &c., founded on the number of stamens, 

 into the adjective form. 



37. THE PISTIL or pistils occupy the centre of the flower ; they are 

 the parts which produce seeds. The pistil has three parts ; the hollow 

 portion below, the ovary; a more or less prolonged stalk above this, the 

 style, which has a variously shaped termination, the stigma. The ovary 



