362 VARIOUS PLANT OROUPS 



ovary. Such placentte are termed parietal.^ The capsule in 

 poppies opens pecuharly 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 tyj)ical 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 ivith the floral envelopes most often in whorls of 

 two, the stamens usually numerous, the pistil alivays compound, 

 one-celled and with parietal placentce, and the seeds albuminous 

 with the embryo sometimes curved but neither coiled nor bent. 



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, 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 popjoy 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 familj^ there are two outer and shorter stamens, 

 alternating with two inner pairs of longer ones. Botanists 

 regard these inner pairs as representing eat'h 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, -f- , connecting the number in the 

 whorl with the numl)cr of sots. 



The carpels of the mustard family are normally only two, 



' P;i-ri'e-tal < L. parictnlin, belonging to a wall < paries, a wall; 

 indicated by the symbol () placed after the number of the carpels. 



^ Por-i-ci'dal < L. poms, pore; cicdirr, to cut; indicated by the 

 sign" placed after that of the pericarp. 



' E-brac'te-ate < L. e, without; hracica, bract. Bo. 



