NATURAL HISTORY OF PLANTS. 



We first notice the outer envelope, a circle, or whorl of five 

 leaves, which form the ca/^x ; these are the sepals {s). Two of 

 them are in front by the bract {h), which is 

 below the flower; two others are lateral, 

 and the fifth behind. They overlap in the 

 bud in a quincuncial arrangement or cesti- 

 vation ; the posterior sepal (No. 2) over- 

 lapping its two neighbours, the lateral sepals 

 (Nos. 4, 5) which are each overlapped 

 on both sides, and of the anterior sepals 

 one is quite uncovered (No. 1,) while the 

 Fig. 2. other No. (8) is overlapped on one side and 



AqniUgia vulgaris. Diagram, ovcrlaps ou the othcr. Next, formiug the 

 second envelope, or corolla, come five other leaves alternate with the 

 sepals — i.e., corresponding with the intervals between them. These 

 leaves ov petals (p) overlap in the bud so as to be imbricated, as shown 

 in the diagram. They have no adhesion whatever with one another, 

 and fall separately. 



Within and above the corolla is the androceum, composed of a 

 large number of stamens, or male fecundating organs. If we sup- 

 pose that, as is often the case, and as is represented in the diagram, 

 these are fifty in number, we shall easily perceive that there are first 

 five opposite the sepals, forming the first whorl or verticil. Within, 

 and a little above these, come five others opposite the petals. Next 

 comes a third whorl of stamens opposite the first ; then a fourth 

 alternate with these, and so on, so that we may count ten whorls of 

 stamens, arranged in ten radiating rows, of which five answer to 

 the sepals and five to the petals. 



Each of these stamens, perfectly independent of the others, is 

 formed of a filament, flattened and dilated below, tapering to a point 

 above, where it supports the base of an oval flattened anther, with 

 two lateral cells containing the pollen, or fertilizing dust. Each cell 

 opens, after the expansion of the flower, by a longitudinal cleft near 

 the margin, but often a little nearer the outer than the inner face, so 

 that the anther is slightly extrorsc (figs. 3, 4)'. These fifty 



' After tlie anthers have opened, the cells open 

 out (as seen in fig. 4) so as to become plane, and 

 are placed edgewise ; they then touch along the 

 whole of their outer surfaces, while the inner 

 •urfaces, covered with grains of jjollen, which 



soon fall, look laterally and outwards. The 

 pollen-grains are elongated, with three equidistant 

 longitudinal grooves. The anthers of the superior 

 stamens are the first to dehisce, shed their pollen, 

 and then turn black. 



