FLOWERS. 37 



radicles of water-plants often show the rotation of 

 the protoplasm very distinctly. 



Flowers. The various parts of flowers, being each 

 a modified leaf, present the same general structure 

 as the latter. As the reader may not be acquainted 

 with the names of these parts or organs in the higher 

 plants, and as we shall have to compare them with 

 their representatives in the lower forms of vegetable 

 life, it will be well briefly to indicate them. A com- 

 mon and beautiful yet despised flower (PI. I. fig. 32) 

 may serve for illustration ; this is chickweed (Stella- 

 ria media) } which can be found everywhere. The 

 outermost circle of flower-leaves, which forms a kind 

 of cup to the rest of the flower (a), is the calyx ; the 

 separate leaves being called the sepals. The row 

 within this, in most flowers consisting of brilliantly 

 coloured pieces, forms the corolla (b) ; the individual 

 pieces being the petals. When the two kinds are 

 equally coloured, or not distinguishable, the whole is 

 called the perianth, as in a tulip. When the seg- 

 ments of the perianth are dry and chaffy, as in the 

 flowers of grasses, the outermost are said to con- 

 stitute the glumes, and the innermost the palea. 

 Within the ring of petals are certain thread-like 

 organs called stamens (c) ; and these consist of a 

 filament (fig. 39 ), surmounted at the top or apex by 

 the anther (fig. 39 b), which is usually coloured, and 

 consists of two lobes. The anthers when ripe burst, 

 and discharge a coloured dust; this is the pollen. 

 Lastly, within the stamens is the central organ of the 

 flower, the pistil, and sometimes there are several of 

 them. The pistil consists of three parts, viz. a swollen 

 base, the ovary (fig. 41 b), surmounted by a column 

 or style (fig. 41 a), and which is crowned by a viscid 

 and often hairy summit, the stigma (fig. 40*). In 

 chickweed there are 3 styles. 



It must be remarked that, in the flowers of some 

 plants, stamens alone are present, while others COn- 



