38 POMOLOGY 



are structurally the most advanced of any within the flower- 

 bud. 



38. Petals. — Almost as soon as the primordia of the sepals 

 are formed, those of the petals appear, the latter in a cycle 

 within and alternating with the former.^ "Development is 

 less rapid than in the case of the sepals but each outgrowth 

 gradually assumes a thin scale-like appearance, more or less 

 sickle-shaped in longitudinal section, and narrowly attached 

 at the base. Each petal finally assumes an acute angle with 

 the calyx and together they roof over the cup-shaped torus." 



39. Stamens. — -" Directly after, or in some instances even 

 at the same time that the primordia of the petals are being 

 laid down, those for the stamens appear. They occur in 

 three cycles. Those of the outermost cycle, directly within 

 the petals, are laid down first, though they are immediately 

 followed by the other two, in fact in some cases all three 

 apparently form at the same time though the outermost 

 cycle always develops the most rapidly. The outermost 

 cycle arises so near to the primordia of the petals that in some 

 sections they appear almost if not quite connected, though as 

 a rule they are veiy distinct. This cycle consists of five pairs 

 of primordia, each primordium appearing at first as a blunt, 

 broad protuberance scarcely to be distinguished from a petal 

 primordium. The middle and innermost cycles each consist 

 of but five primordia. It is a difficult matter to decide 

 whether there are actually three or but two cycles of stamens 

 inasmuch as the two inner cycles are extremely close together. 

 From an examination of many sections and dissections, 

 however, the conclusion that there are actually three, seems 

 to be well founded. The young stamen rapidly assumes a 

 distinctly bi-lobed appearance; the basal lobe is short and 

 slender while the apical broadens out, and it in turn becomes 



1 The following quotations are from E. J. Kraus, Ore. Agr. Exp. Sta. 

 Res. Bull. 1, part 1. 1913. 



