86 BRANCHING, ETC., OF STAMENS [CH. 



lobes with regard to the centre of the flower, for the 

 dehiscing faces may be turned inwards (introrse) or out- 

 wards (extrorse), and various combinations of these cha- 

 racters of attachment to the filament and aspect of 

 anther-lobes occur. 



As to the mode of dehiscence of the anther, while it is 

 most frequently effected by means of slits (sutured), it 

 occurs in some cases by means of incomplete slits or pores 

 (porous) at the base or apex of the anther e.g. Solanum, 

 Ericaceae, Polygala, &c. ; or the dehiscence may take place 

 by means of opercular openings (valvular} in the sides of 

 the thecse, the lid of which is an excised piece of anther- 

 wall, e.g. Sassafras, Barberry, and other Berberidete and 

 LauraceaB. 



Hitherto I have had regard to the simple typical 

 stamen only, as commonly met with, but in many flowers 

 e.g. Mallows, some Myrtacese, and Ricinus the stamens 

 are branched, and in others they are confluent in various 

 degrees, so that we have bundles or groups of stamens, 

 as in Papilionaceae, Poly gala, &c., and these groupings are 

 distinguished in descriptive botany. 



Monandrous or one-stamened flowers are not common, 

 but they occur in Euphorbia, Zoster a, and a few other plants. 

 In the commoner cases the number of stamens has some 

 relation to that of the other parts of the flower, and the 

 corresponding Greek numerals are prefixed for technical 

 terms e.g. pentandrous, decandrous, &c. and if more than 

 twenty, polyandrous or indefinite. But these numerical 

 terms apply to the individual free stamens. Where the 

 stamens are equal in number to the sepals and petals the 

 flower is said to be isostemonous ; where the number of 

 stamens is double that of the petals, the flower is 

 diplostemonous. It commonly occurs, however, that diplo- 

 stemonous stamens do not regularly alternate with the 



