THE POLYPETALOUS ORDERS. 



393 



731. Sllbord, Sderantheae (the Knawel Family) is like the last, 

 only there are no stipules, and the calyx-tube is urceolate in fruit, 

 inclosing the utricle. Ex. Scleranthus. 



732. Subord, MollllgineflB (the Cafpet-weed Family), is apetalous, 

 exstipulate, and has the stamens alternate with the sepals when of 

 the same number; thus effecting a transition to the next order. 

 Ex. Mollugo. 



733. Ord, Portlllacacese (the Purslane Family). Succulent or 

 fleshy herbs, with alternate or opposite entire leaves, destitute of 

 proper stipules, and usually ephemeral flowers. Calyx mostly of 

 two or three sepals, cohering with the base of the ovary. Petals 

 five, or rarely more numerous. Stamens variable in number, but 

 when equal to the petals situated opposite them. Styles two to 

 eight, united below. Capsule with few or numerous seeds, attach- 

 ed to a central basilar placenta, often by slender funiculi. Seed 

 and embryo as in Caryophyllacese. Ex. Portulaca (Purslane), 



Claytonia (Fig. 561). Chiefly natives of dry and arid places in 



FIG. 561. Claytonia Virginica (Spring Beauty). 562. Young fruit and the persistent two- 

 leaved calyx. 563. Section of the dehiscing capsule. 564. A seed. 565. The same, vertically 

 divided. 566. The embryo detached. 



FIG. 567. Flower of the Purslane ; the calyx cut away at the point where it adheres to the 

 ovary, and laid open. 568. A capsule (pyxis, 616) of the same, transversely dehiscent. 



