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Show 136 HETEROSTYLED DIMORPRIC PLANTS. CHAP. III. deserves notice that in the homosty led genera, as I am informed by Professor Asa Gray, the stamens are either exserted or are included within the tube of the corolla, in a nearly constant manner; so that this character, which is not even of specific value in the heterostyled species, is often of generic value in other mem hers of the family. CHAP. IV. LYTHRUM SALICARIA. 137 CHAPTER IV. flETEROSTYLED TRIMORPHIO PLANTS. Lythrum salicaria-Description of the three forms-Their power and complex manner of fertilising one another-E1ghteen different unions possible-Mid-styled form eminently feminine in natureLythrum Grrefferi likewise trimorphic-L. tliymifulia dimorphicL. hyssopifolia homostyled-Nesrea verticillata trimorpbic-Lagerstroomia, nature doubtful-Oxalis, trimorphic sp cies of-0. Valdiviana- 0. Regnelli, the illegitimate unions quite banen-0. speciosa- 0. sensitiva-Homostyled species of Oxalis-Pontcdoria, the one monocotyledonous genus known to include hoterostyled species. IN the previous chapters various heterostyled dimorphic plants have been described, and now we co1ne to heterostyled trimorphic plants, or those which pr sent three forms. These have been observed in three families, and consist of species of Lythrum and. of the allied genus N esrea, of Oxalis and Pontedoria. In their manner of fertilisation these plants offer a more remarkable case than can be found in any other plant or animal. Lythrttm salioaria.-The pistil in each form differs from that in either of the other forms, and in each there are two sets of stamens different in appearance and function. But one set of stamens in each form corresponds with a set in one of the other two £ rms. Altogether this one species includes three females or female organs and three sets of male organs, all as distinct from one another as if they b longed to different species; and if smaller functional differences |