Part 110. The mustard family (Cruciferae) agrees closely with the poppy family in general form and floral structure, as may be seen by comparing our figures of cabbages, turnips, mustards, and rape (Brassica), watercress and horseradish (Nasturtium), and radish (Raphanus). The main family differences are in the bracts and bractlets, the number of stamens, and peculiarities of the gynoecium.

While the members of the poppy family have bracts and often bractlets of the usual sort (which therefore do not call for special notice), the members of the mustard family are almost unique in having no bracts within the inflorescence. Hence they are described as ebracteate.1 In a flower of the mustard family there are two outer and shorter stamens, alternating with two inner pairs of longer ones. Botanists regard these inner pairs as representing each a single stamen branched or divided into two.

1 E-brac'te-ate - L. e, without; bractea, bract. Bo.

The fact that a whorl is thus divided into sets is expressed in our formulas by the sign of division, ÷, connecting the number in the whorl with the number of sets.

The carpels of the mustard family are normally only two, as in certain of the poppy family, but the ovary instead of being one-celled is divided into two compartments by a partition extending between the parietal placentae. When ripe the carpels mostly separate from the placentae and from this partition. Such a fruit is called a silique.2 The ovules differ from any we have seen among the plants of the crowfoot order in lacking a raphe and being curved to a somewhat kidney-like form. When thus curved, ovules are described as campylotropous.3

2 Si-lique' - L. siliqua, a pod; Ci-.

3 Cam-py-lot'ro-pous - Gr. kampylos, curved; trope, a turn. E oe.

The seeds are almost always exalbuminous and have the embryo commonly bent in various ways-a peculiarity expressed in the formulas by G ^.

Note how closely similar are the formulas of Brassica, Nasturtium, Raphanus, and Cruciferae given on pages 406, 407.

As a definition of the family we have thus:-

Mustard family: mostly herbs without milky or colored juice or oil reservoirs, often of sharp taste though pleasant flavor; ebracteate inflorescence; usually hypogynous flowers with all the parts in whorls of two (with the apparent exception of the four inner and longer stamens), the ovary divided into two cells by a partition joining the parietal placentae; the fruit almost always a silique with exalbuminous seeds having the embryo variously bent.