Part 109. The poppy family (Papaveraceae) is represented sufficiently well for our purpose by the opium poppy (Papaver somniferum). Like all the other species of its genus, it contains instead of volatile oil a milky juice from which, as we have seen, opium is obtained. Many other genera of the family contain a similar juice which in some cases is bright yellow, and in others red. Sometimes the juice is watery.

The main structural features of Papaver appear in its formula on pages 406, 407.

The only new features calling for special notice concern the gynoecium which, unlike any in the crowfoot order (except possibly in the laurel family), consists of several carpels so united as to form a compound pistil with a one-celled ovary. That is to say, the carpellary leaves as they grow have the right edge of one coalescent with the left edge of its neighbor. The united edges of neighboring carpels thus form placentae which lie along the outer wall of the compound ovary. Such placentae are termed parietal.l The capsule in poppies opens peculiarly by little pores like windows under the eaves of the overhanging stigma-ring. Such opening by pores, is called poricidal2 dehiscence.

1 Pa-ri'e-tal - L. parietalis, belonging to a wall - paries, a wall; indicated by the symbol () placed after the number of the carpels.

2 Por-i-ci'dal - L. porus, pore; coedire, to cut; indicated by the sign0 placed after that of the pericarp.

With but slight modifications, not calling for special comment, the formula of Papaver becomes typical of the family as shown on pages 406, 407.

The family may generally be recognized as being mostly herbs, commonly having a milky or colored juice, and hypogynous flowers with the floral envelopes most often in whorls of two, the stamens usually numerous, the pistil always compound, one-celled and with parietal placentae, and the seeds albuminous with the embryo sometimes curved but neither coiled nor bent.