86 



STAMENS. 



Since in every species of plant the number of stamens remains constant, thus in 

 the Mare'stail (Hippuris) there is one, in Lilac two, in Iris three, in the Woodruff 

 four, in the Violet five, and in the Tulip six stamens, their number has been made 

 the basis of a classification of flowering plants at once convenient and popular, 

 though not strictly scientific. In the well-known System of Linnseus plants are 

 arranged into groups called Classes, in which the first class (Monandria) includes 

 all forms with a single stamen, the second (Biandria) those with two stamens, and 

 so on. 



The aggregate of stamens in a flower is termed the Androecium. As a rule the 



Fig. 213. — Stamens of double and monstrous flowers. 



1 Vertical section of a green flower of Primula japonica. 2 Vertical section of a double flower of Primula spectal)Uifi, 

 8-8 Isolated stamens from the same flower. » Stamen from a green flower of the Tiger Lily {Lilium tigrinum). 18^ u Folia- 

 ceous stamens from a flower of Campanula Trachelium. 12 Green flower of Saxifraga atellaris. i« A single stamen from 

 the same flower. (All the figures enlarged.) 



andrcEcium is inserted between the leaves of the perianth and the carpels, so that 

 from without inwards the sequence is perianth, stamens, carpels. Sometimes the 

 carpels are wanting, so that the stamens constitute the inmost members of the 

 flower ; similarly also carpels may be present but no stamens. 



We distinguish in a stamen that portion which is concerned in the production of 

 Pollen — the Anther — and its stalk, the Filament. The stamens in many flowers are 

 partly metamorphosed into petals; indeed, there are grounds for believing that all 

 petals have been originally modified from stamens. What are known as "double 

 flowers" are often flowers in which the stamens have given place to petals. All 

 inteimediate stages between stamens and petals can be seen in double-flowered 

 Roses, Carnations, and Primulas (cf. figs. 213 *> *■ ^- *■ ''). Not infrequently, at the 



