254 ORGAXOGRAPHT. 



four heads, namely: — 1. Number, 2. Insertion or Position, 

 3. Union, 4. Relative length. 



1. Number. — The number of stamens in the flower is subject 

 to great variation, and several terms are in common use to in- 

 dicate them. 



In the first place, certain names ai*e applied to define the 

 number of the stamens Avhen compared with the sepals and 

 petals. Thus when the stamens are equal in number to the 

 sepals and petals, the flower is said to be isostemenous. as in the 

 Primrose ; if they are unequal, as in the Valerian tlie flower 

 is anisoslemenous, or when greater accuracy is required in the 

 latter case, M-e say diplostemenous, if the stamens are double the 

 number, as in Stonccrop, meiosfemenous, if less in number, as 

 in the Lilac, and polystemenous, if more than double, as in the 

 Eose. 



Secondly, the flower receives different names according to the 

 actual number of stamens it contains, without reference to the 

 outer whorls. This number is indicated by the Greek numerals 

 prefixed to the word androus, which means male or stamen. 

 Thus :— 



A flower having One stamen is Monandrous, as in Hippuris. 



„ „ Two stamens is Diandrous, as in the Ash and 



Privet. 



„ „ Three stamens is Triandrous, as in most 



Grasses. 



„ „ Four stamens is Tetrandrous, as in the Holly 



and Plantain. 



„ „ Five stamens is Pentandrous, as in tlie Cows- 



lip and Convolvulus. 

 „ Six stamens is Hexandi'ous, as in the Lily and 

 Tulip. 



„ „ Seven stamens is Heptandrous, as in the .^s- 



culus and Trien talis. 



,, „ Eiglit stamens is Octandrous, as in the Ivy and 



Heaths. 



„ „ Nine stamens is Enncandrous, as in the Flower- 



ing Rush. 



„ „ Ten stamens is Decandrous, as in the Pink and 



Saxifrage. 



„ „ Twelve stamens is Dodecandrous, as in the 

 Asarabacca, 



„ „ Twenty stamens is Icosandrous, as in the 



Strawberry. 



„ „ Kumcrous stamens is Polyandrous, as in the 



Puit])y and Watcr-Lily. 



We shall have to reier to tliesc terms again when treating of 

 tlie Linnaian svstcm of classification as some of the classes in 



