118 JOUKNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



they are called, and the complete petal of a field Buttercup. Hence we 

 discover that one way of making a petal is to construct it out of an 

 anther. The filament plays no part, merely remaining as a little stalk to 

 support the nectary. 



If now we compare this with a Water Lily, we shall find that it is the 

 filament and not the anther which makes the petal. There is a perfect 

 transition between stamens surrounding the pistil, each having a narrow 

 filament and long anthers ; but as one passes from the centre to the 

 circumference of the flower, we find the filaments broadening and the two 

 cells 6f the anther disappearing, first from one side then from the other, 

 so that at last a perfect petal is obtained. A similar transition may be 

 seen in imperfectly double Roses (fig. 41). 



The next process, which is already partly effected in Buttercups, is to 

 reduce the number of parts, if numerous, and make whorls instead of 

 spiral arrangements. 



In a Buttercup the sepals make a whorl, and the petals another whorl 

 of five parts in each ; but the stamens and carpels are very numerous and 

 arranged in spirals. The interpretation of the number 5 is very simple. 

 If a shoot of a Rose, May or Oak be examined, let any leaf be called 

 -No. 1. Then, if a line be traced from leaf to leaf, it will be found to 



describe a spiral round the shoot, until a leaf (the 6th) is in the same 

 vertical line as No. 1. These five leaves constitute a "cycle ; " the 6th 

 begins the next cycle ; and so on. If these five leaves could be brought 

 to the same level by an arrest of the internodes between them we should 

 ■ have a whorl. Such is the origin of the calyx and corolla ; but with one 

 exception ; the two whorls would be exactly over one another, each sepal 

 being covered by a petal ; but to avoid this, Nature shifts the corolla, so 

 to say, that the petals may fall in heticeen and not over the sepals. 



In making flowers, the typical arrangement comes to be as follows : 

 "5 sepals, 5 petals, 5 stamens, 5 more stamens and 5 carpels, each whorl 

 alternating with the next. Such is seen in the flower of Geranium, as 

 shown in the diagram (fig. 42). The dots represent five honey-glands. 



From this complete stage reductions often occur, as by suppressing 

 one whorl of stamens and some of the carpels, often lea^-ing only two. 

 As an example, w^e may take Geranium, which has the above quinary 

 arrangement, but the allied genus Erodium, or Stork's-bill, has only one 

 whorl of stamens. In St. John's Worts the pistil is reduced to three 

 •carpels only, and in Pinks to two. 



Sometimes flowers are binary, the parts being in twos, as of the 

 Enchanter's Nightshade (fig. 43) ; or they may be quaternary, the whorls 

 being partly in fours, as are the sepals and petals of the Lilac and Privet. 



Fig. 42. — Diagram of flower of 

 Geranium. 



Fig. 43. — Diagram of flower of 

 Enchanter's Nightshade. 



