ROSACEA. 193 



Group 13. Ovaries one or several, simple and distinct, or combined into a compound 

 ovary of 2 or more cells, with the placentiE in the axis. Flowers regular. 

 Petals and (distinct) stamens inserted on the calyx. Albumen none. 



Order XXXVIII. ROSACE.E. Juss. The Rose Tribe. 



Sepals 5 (rarely 3 or 4), more or less united, often with as many bracts ; the 

 odd one superior, or next the axis. Petals as many as the sepals (rarely none), 

 inserted on the edge of a thin disk that lines the calyx. Stamens indefinite, 

 rarely few. Ovaries solitary or several, with 1 - 2 or sometimes more ovules : 

 styles often lateral. Fruit either a drupe, a pome, achenia, or follicular. 

 Embryo straight: cotyledons flat or plano-convex. — Trees, shrubs or herba- 

 ceous plants, with alternate leaves, and usually furnished with conspicuous 

 stipules. Flowers mostly handsome. 



CONSPECTUS OF THE SUBORDERS. 



1. Amygdale^:. Calyx free from the ovary, deciduous. Ovary solitary, with two suspended ovules, and a terminal 



style. Fruit a drupe. — Trees or shrubs. 



2. Rosacea proper. Calyx often bracteolate, and appearing double. Ovaries several or numerous, rarely solitary, 



free from the calyx, but sometimes enclosed in its persistent tube : styles terminal or lateral. Fruit follicular, or 

 consisting of numerous achenia. — Trees or shrubs. 



3. PoMEa;. Calyx campanulate or urceolate ; the tube becoming very thick and fleshy, including and cohering with 



the ovaries. Fruit a pome, with one or few ascending seeds in each cell. 



Suborder I. Amygdale^. Juss. 



Calyx free from the ovary, deciduous. Ovary solitary, with 2 collateral suspended 

 ovules : styles terminal. Fruit a drupe. Seed mostly solitary ; the funiculus 

 adhering to the side of the cavity of the ovary. — Trees or shrubs, with simple 

 leaves. Stipules free. Fruit mostly eatable ; the kernel (as well as the leaves) 

 yielding hydrocyanic acid (prussic acid).* 



* The seeds of Amygdalese do not contain the prussic acid ready formed, but two peculiar principles called amygdaline 

 and emulsine, which are contained in distinct cells. When the kernels are bruised, and especially when heat is applied, 

 these substances immediately react on each other, giving rise to the formation of prussic acid, together with souie other 

 products. 



[Flora.] ,. 26 



