24 MORPHOLOGY OF ANGIOSPERMS 



leaf ; Ricinus, in which repeated forking results in a stamen, 

 bearing very numerous sporangia; and Hypericum, in which 

 the primordium branches, that is, produces secondary primor- 

 dia, the common base of the tufted cluster not being recognized 

 in the mature condition. The case of zonal development, that 

 is, an uprising from the whole staminiferous zone, and also the 

 case of stamen and petal or stamen and carpel regions rising 

 en masse, have already been noted in connection with the gen- 

 eral tendencies of the flower. The tendency of stamens and 

 of carpels to become more or less coalescent through pressure is 

 also well marked, as in the anthers of Compositae and Lobe- 

 liaceae, and in some cases that have been called syncarpy. It 

 remains to note the fact that stamens occur in all stages of 

 abortion, especially to be observed among the Personales, from 

 the absence of sporangia to that amount of abortion that is 

 only short of suppression. Stamens that have lost their normal 

 function are generally called " staminodia," but they may as- 

 sume various forms and serve a variety of purposes. In certain 

 cases, as notably among the Labiatae, the claim that one or 

 more stamens have been suppressed is justified by their pres- 

 ence in near relatives, combined with the occurrence of unoc- 

 cupied points where stamens ordinarily appear. 



The carpel set has been called collectively the " gynoecium,"' 

 a term that also should be dropped from morphological ter- 

 minology on account of its implication of sexuality. The carpel 

 is the organ most intimately related to the megasporangia, in- 

 vesting them more or less completely, but not always producing 

 them, and giving name to the Angiosperms. Its history is un- 

 known, for although it is easy to imagine it derived from such 

 open carpels as are found among Gymnosperms, no clear inter- 

 mediate stages have been found. At all events, it is a thor- 

 oughly established and characteristic organ. The term ".ovary " 

 for the sporangium-bearing cavity is particularly unfortunate 

 on account of its very different application among animals. 

 To avoid this confusion Barnes * has proposed the term " ovu- 

 lary," but even this contains in its stem the sexual implica- 

 tion. The style is definitely related, in its varying form and 

 length, to the problem of pollination, and upon it the stig- 



* BARNES, C. R. Plant Life. 1898. p. 240. 



