304 TEXTBOOK OF BOTANY 



314. The Mustard Family. — The plants of this family are 

 nearly all herbs, many of them with sharp-tasting substances 

 in their stems, roots, or seeds. The flowers are regular, with 

 four sepals, four petals, two short and four long stamens, 

 and one two-parted pistil. The fruit is usually a pod-like 

 structure whose wall when it is ripe splits into two parts 

 that separate from a central partition to which the seeds are 

 attached. Among the many cultivated or useful plants 

 that belong to the mustard family are the radish, turnip, 

 rutabaga, rape, cabbage, cauliflower, Brussels sprouts, kohl 

 rabi, the mustard, horseradish, garden cress, and water cress. 

 Sweet alyssum, the candytufts, and the stocks or gilliflowers 

 are raised for their flowers. Among the common weeds of 

 the family are various mustards and the shepherd 's purse. 



315. The Saxifrage Family. — This family and the next 

 are closely related. Most of the members of both have 

 regular flowers, with five sepals and five petals. Most of the 

 plants of the saxifrage family have not more than ten stamens 

 and fewer macrospore leaves than sepals ; often the macro- 

 spore leaves are united to form a compound pistil. The most 

 important members in cultivation are the currants and goose- 

 berries. Among those grown for ornamental purposes are 

 the mock-orange (commonly called " syringa "), the hydran- 

 geas and hortensia, and deutzia. 



316. The Rose Family. — The members of this family 

 differ from those of the preceding one as a rule in having more 

 numerous — sometimes very numerous — stamens, and more 

 than otie pistil — usually at least as many pistils as sepals. 

 The pistils are simple. The seeds are usually without endo- 

 sperm, whereas the seeds of the saxifrage family contain 

 endosperm. The rose family includes the great majority 

 of plants that are cultivated for their fruits, at least in tem- 

 perate countries, as well as many ornamental plants. One 

 division of the family includes Spircea, some of whose species 

 are ornamental shrubs. The members of another division 



