142 COMPOUND ORGANS OP PLANTS. 



necessarily sterile ; but if some of the stamens are perfect, 

 even in a double flower, there may be fruit. 



The number of stamens which compose the andrcecium 

 varies very considerably. There" may be only one, as in Calli- 

 triche verna, Water star grass, or many hundreds as in the 

 poppy. The flower, according to the number of its stamens 

 from one to ten, is said to be monandrous (^6vo? one, avrjp male,) 

 diandrous (5tj two,) triandrous (tpsis three,) tetrandrous (tetpas 

 four,) pentandrous (itfvte five,) hexandrous (2 six,) heptan- 

 drous (Jrt-ra seven,) octandrous (6xtu eight,) enneandrous (fWta 

 nine,) decandrous (filxa ten.) Above ten there is no regularity 

 in the number of the stamens. All flowers having from twelve 

 to twenty stamens, are designated as dodecandrous (fiwS sxa, 

 twelve;) and if their number exceeds twenty, Polyandrous 

 (rtoXuj many.) 



Proportion of the stamens. The relative length of the 

 stamens is not always the same, the filaments being sometimes 

 more or less developed in the same flower. In some cases 

 there exists a definite relation as regards number between the 

 long and the short stamens. When a flower encloses four 

 stamens of which two are constantly the longest, it is called a 

 didynamous flower, (Stj twice, and Swa/us power;) Fig. 44 ; 

 and when there are six stamens in the same flower and four of 

 them longer than the other two, the flower is said to be tetra- 

 dynamous, (tsipas four, and &vva/u$ power ;) Fig. 45. The 

 natural orders Labiatae and Scrophulariacese furnish us with 

 samples of the first, and Cruciferae of the last disposition of 

 the stamens. In the wood sorrel, (Oxalis,) there are ten 

 stamens, monadelphous at their base, five long and five short, 

 which alternate with each other. 



Connexion of the stamens. The stamens, in common with 



