362 VARIOUS: PLANT GROUPS 
ovary. Such placentze are termed parietal.1_ 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 poricidal ? dehiscence. 
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 hypogy- 
nous flowers with the floral envelopes most often in whorls of 
two, the stamens usually numerous, the pistil always compound, 
one-celled and with parietal placente, and the seeds albuminous 
with the embryo sometimes curved but neither coiled nor bent. 
110. The mustard family (Cruciferz) 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, pages 54, 66-70), watercress 
and horseradish (Nasturtium, pages 70, 71, 144), and radish 
(Raphanus, page 55). The main family differences are in the 
bracts and bractlets, the number of stamens, and peculiarities 
of the gyncecium. 
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.* 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. | 
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, 
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; cedire, to cut; indicated by the 
sign® placed after that of the pericarp. 
3 E-brac’te-ate < L. e, without; bractea, bract. Bo, 
