518 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



but as it gathered strength in the summer, there was a contest between 

 vigour and leaf -growth ; so that though the blade was large it could not 

 complete the enlarged oval outline. Hence arose the "lobing." If this 

 be carried to excess the lobes become separate leaflets. An advantage to 

 the tree or shrub is that, there being many small blades instead of large 

 ones, light can fall between them and so reach the underlying or inner 

 ones within the plant. 



III. Origin op the Floral Whorls. 



The Nature of a Flower. — A flower-bud is essentially the same thing 

 as a leaf-bud, in that every separate part of a flower might have grown 

 into a leaf, and such is sometimes the case abnormally. Thus the 

 " green " Rose * is a foliaceous or leafy form of a " China " Rose. It is 

 " double " in that it possesses many parts ; but the carpels, stamens, 

 and petals are all represented by green leaves ; the staminal leaves often 

 have one or two anther-cells along the margins. 



Bracts. — The bracts, from the axil of which flower-buds arise, are 

 also modified leaves. In some plants they are true leaves, but much 

 reduced in size ; such occurs on Willow-herbs, Beetroot, and Toad-flax. 



More frequently a bract represents the petiole or else the blade only. 

 Thus a perfect transition between a complete leaf and a floral bract can 

 be seen on the Hellebore. As the stalk widens and shortens, the separate 

 lobes of the blade become reduced in size and number, till nothing but an 

 oval, pointed bract remains. 



In Buttercups the reverse takes place, as the stalk is arrested and 

 the segments of the blade decrease in size until a bract is formed consist- 

 ing of two or even one only. 



Sepals. — These are usually "homologous" with petioles only, as 

 may be seen in any Rose, in which the outermost sepals of the five, at 

 least, are still provided with rudimentary leaflets. 



A common monstrosity of Primroses is for the upper part to develop 

 into five true leaf-blades. Such Primroses are called " Jack-in-the- 

 Green." 



Petals. — These appear to have been made out of stamens, and not 

 directly from leaves, as bracts and sepals were. 



For certain plants, such as Water lilies and Cannas, have retained 

 the transitional forms, so that a complete series from true stamens to 

 true petals can be readily observed. 



The filament widens and the anthers gradually disappear till petals 

 are formed. 



Stamens. — These existed long before petals were formed, as still shown 

 ljy existing gymnosperms ; and they take their origin out of green leaves. 

 Such are still visible in Junipers and Cypress, &c, wherein the stamen 

 consists of a green scale bearing the anther-cells at the base. In Finns 

 the upper part of the scale is yellow like the anther-cells themselves. 



Yellow thus seems to have been the earliest known colour, other than 



* This curious Rose was issued to the trade in 185(5. It appeared in the catalogue 

 of MM. Guillot ptre et Clement of Lyons as Rosa viridiflora, "a fieurs vertes, fl. 

 moy. vert fonc6, couleur du feuillage." 



