THE POLYPETALOUS ORDERS. 



413 



ly solitary, free from the calyx (which is often bracteolate, as if 

 double), but sometimes inclosed in its persistent tube, in fruit be- 

 coming either follicles or achenia. Styles terminal or lateral. 

 Herbs or shrubs. The three tribes of this suborder are Tribe 1. 

 SPIREJE, where the fruit is a follicle. Ex. Spiraea and Gillenia. 

 Tribe 2. DRYADE^E, where the fruits are achenia, or sometimes 

 little drupes, and when numerous crowded on a conical or hem- 

 ispherical torus. Ex. Dryas, Agrimonia, Potentilla, Fragaria 

 (Strawberry), Rubus (Raspberry and Blackberry). Tribe 3. Ro- 

 SE.E, where numerous achenia cover the hollow torus which lines 

 the urn-shaped calyx-tube ; and the latter, being contracted at the 

 mouth, and becoming fleshy or berry-like, forms a kind of false 

 pericarp ; as in the Rose. 



777. Subord, Pomes (the Pear Family). Ovaries two to five, or 

 rarely solitary, cohering with each other and with the thickened 

 and fleshy or pulpy calyx-tube ; each with one or few ascending 

 seeds. Trees or shrubs. Ex. Crata?gus (the Thorn), Cydonia 

 (the Quince), Pyrus (the Apple, Pear, &c.). 



778. This important order is diffused through almost every part 



of the world ; but chiefly abounds in temperate climates, where it 



FIG. 684. Vertical section of an unexpanded Rose, showing the attachment of the carpels to 

 the lining of the calyx-tube, and of the stamens and petals to its summit or edge. 685. Vertical 

 section of the fruit of the Quince, exhibiting the carpels invested by the thickened calyx which 

 forms the edible part of the fruit ; one of the ovaries laid open to show the seeds. 686. A mag- 

 nified seed ; the raphe and chalaza conspicuous. 637. The embryo. 688. Cross-section of an 

 apple. 639. Flower, &c., of the American Crab- Apple (Pyrus coronaria). 



35* 



