LYTHRUM SALICARIA.
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CHAPTER IV.
Heterostyled Trimormiic Plants.
Lythrum snlicaria —Description of the three forms—Their power andcomplex manner of fertilising one another—Eighteen differentunions possible—Mid-styled form eminently feminine in nature—Lythrum Grsolferi likewise trimorphie — L. tliymifolia dimorphic—L. liyssopifolia liomostyled—Nessea verticillata trimorphie—Lager-streomia, nature doubtful—Oxalis, trimorphie species of—O. Valdi-viana—O. Reguelli, the illegitimate unions quite barren—O. spe-ciosa—O. sensitiva—liomostyled species of Oxalis—Pontederia,the one monocotyledonous genus known to include heterostyledspecies.
In the previous chapters various heterostyled dimor-phic plants have been described, and now we come toheterostyled trimorphie plants, or those which presentthree forms. These have been observed in threefamilies, and consist of species of Lythrum and of theallied genus Nessea, of Oxalis and Pontederia. Intheir manner of fertilisation these plants offer a moreremarkable case than can be found in any other plantor animal.
Lythrum salioaria. —The pistil in each form differsfrom that in either of the other forms, and in eachthere are two sets of stamens different in appearanceand function. But one set of stamens in each formcorresponds with a set in one of the other two forms.Altogether this one species includes three females orfemale organs and three sets of male organs, all asdistinct from one another as if they belonged to dif-ferent species; and if smaller functional differences