AUTHOR'S INTRODUCTION. 5 



Thistle) generally have four whorls or sets of parts, al- 

 though there are some species with one or more of these 

 whorls missing or suppressed e.g. Hazel, Willow. 



In the centre is the pistil, or ovary, which may be com- 

 posed of one (e.g. Primrose) or more (e.g. Celandine) pieces. 

 It is, however, never composed of tube-shaped structures, 

 though often made up of separate carpels, which may 

 burst when ripe (e.g. Marsh Marigold). 



Stamens form a whorl, in some way surrounding the 

 pistil, and these again are never tube-shaped. The dust- 

 like pollen grains come from the anthers of the stamens. 

 In the Primrose the stamens are fixed on the petals or 

 corolla, and in this way surround the central pistil. 



Petals are usually large, brightly-coloured, rather thin 

 and conspicuous . They form a whorl fixed around, 

 and generally fitted in below, the stamens. The petals 

 together form the corolla. 



Sepals are usually greenish in colour. They form, when 

 present, the outermost ring or whorl, are fixed on below 

 or outside the petals, and are together known as the calyx j 

 because they form a sort of cup-shape when united. 



Some flowers have no pistil or ovary, others no stamens, 

 while some have no sepals, others no petals, and a few are 

 destitute of both sepals and petals. There must always be 

 present, however, either pistil or stamens, or both, as they 

 are of more importance to a plant than either petals or sepals: 



Simple flowers are of many different shapes and struc- 

 tures, but only two kinds need special mention here. 

 Many flowers (e.g. Primrose) have their petals so joined 

 together as to form a corolla in one piece. In this flower 

 the number of petals composing the corolla is evidently 

 five, but in many others the shape of the corolla gives no 

 idea of the number of petals. 



Lipped flowers have their petals so joined as to form 

 a corolla (generally in one piece, and more or less tubular), 

 which is divided at the mouth into an upper and a lower 

 lip, each of which may be again divided so as to assume 

 a great variety of forms. In the White Dead-Nettie 

 the lips are open or gaping, while in the Snapdragon and 



