INTRODUCTION 



Campanula, it is persistent, remaining in a withered condition 

 round the fruit. 



The (Estivation (Latin cestivus, belonging to summer), or fold- 

 ing of the leaves of the flower in the bud, is often characteristic 

 of Natural Orders or other large groups. In Clematis the sepals 

 are valvate, touching at their edges without overlapping ; in all 

 other Ranunculacece they are imbricate, overlapping like tiles on 

 a roof. Poppies have their petals crumpled. The Malvacece 

 have their sepals valvate and their petals convolute, with one edge 

 towards the centre of the flower, and the other rolled round the 

 next petal. In Convolvulus the coherent petals are convolute and 

 twisted upwards, or contorted. 



Ray-floret of Composite 

 showing ligulate corolla 

 and syngenesious anthers. 



Personate corolla of 

 Toad-flax. 



Ringent corolla of 

 Dead-nettle. 



The Stamens usually consist of one, two, or more whorls of 

 thread-like stalks known as filaments, each surmounted by an 

 oblong or rounded body, generally two-lobed externally and two- 

 chambered within, which is called the anther, and contains the 

 pollen, a fine dust-like substance. When mature the anther 

 bursts and discharges the pollen, which is the active agent in 

 " setting ; ' or fertilising the seed. The number of stamens varies 

 from one to an indefinite number, but is very commonly either 

 the same as that of the petals or twice as many. They may be 

 equal or unequal in length : but if, as in most Labiatce and 

 Scrophulariacece, there are four stamens, two long and two shurt, 

 they are termed didynamous (Greek dis, two, dunamis, strength) ; 

 and if, as in the Crucijerai, there are six stamens, four longer than 



