KOSACE.E 479 



This may be seen by reference to Crataegus Pyracantha, 

 where a similar condition prevails. The globose fruit con- 

 sists of five carpels surrounded by the fleshy receptacle. 

 The walls of the carpels become greatly ossified or, properly 

 speaking, lignified and thickened; and seeing that each carpel 

 or pyrene constitutes the fifth part of a sphere, they are 

 trigonous or wedge-shaped in transverse section, and modify 

 the shape of the seed and embryo in conformity with their own. 

 The loculi in the fruits of the species of Pyrus generally are 

 proportionately large so that they do not affect the shape of 

 the seed. In Pyrus Cydonia, P. japonica, and P. chinensis, 

 the ovules, and afterwards the seeds, are very numerous in 

 each loculus, a most unusual circumstance in the Order. 



Seedlings. As in the seeds so in the seedlings we find a 

 great similarity prevailing amongst the cotyledons of different 

 species and genera throughout the Order. The embryo is 

 amygdaloid, varying for the most part in size, dependent upon 

 the size of the seed, and that again upon the size of the 

 endocarp or the achene. The cotyledons in the seedling stage 

 are nearly all of the same general outline, varying between 

 oval and oblong. They are for the most part shortly petiolate 

 with a slender, rarely a broad petiole, and being either thick 

 or opaque they do not often exhibit much of the venation 

 beyond the midrib. Those which are more or less deeply 

 emarginate form a second type ; while a third form has the 

 lamina cordate at the base. Taking the type, which varies 

 between oblong, oval, and suborbicular, two species might be 

 singled out as extreme modifications. These are the Cherry 

 and Kosa berberidifolia (fig. 322). The first has spathulate- 

 oblong, fleshy, entire cotyledons with glands at the base. The 

 second has narrowly oblong, glandular-ciliate cotyledons with 

 a rather broad petiole. The Spiraeas, having generally very 

 small seeds, have small cotyledons. S. callosa (fig. 311) re- 

 presents one of the shrubby tribe. The primary leaves are 

 small and vary from cuneate to broadly ovate. The ultimate 

 leaves are lanceolate and unequally serrate. 



The cotyledons of Rubus are moderately large, owing to 

 the size of the seed. Those of Rubus phcenicolasius (fig. 312) 

 are shortly oblong, while those of R. rugosus are broadly oval. 



