Morphological forms and polyploidy in Triglochin procea agg. in Victoria.

Abstract

A numerical analysis of intraspecific variation within the Triglochin procera aggregate in Victoria suggests four morphologically distinct forms. Cytological studies indicate the polyploid series 2n = 16, 32, 64, the counts corresponding to three of the morphological forms. The diploid. designated form A. is found in north-central Victoria. It has distinctively small fruits, with 4-6 carpels. The pericarp is membranous, and the seed testa brown, hard and three-ridged. Flowering scapes are reddish. in comparison with the green scapes of the other forms. The tetraploid, designated form B, found in Gippsland, has globose, smooth, untwisted fruits on very short pedicels and terete leaves and scapes. In common with form C, it has a constant carpel number of 6, fruit with a fleshy pericarp, and seed with a smooth, pale, soft testa. The octoploid; form C, is the most widely distributed and the most variable form, particularly with regard to leaf morphology and degree of twisting of the carpels. Leaves are generally fleshy and broad, but may be thinner and trailing in fast-flowing water. Fruits are large. The fourth morphological form; D, is also an octoploid, with fruits like form C, but it has thin trailing. submerged, conspicuously veined leaves which contrast with the robust. emergent leaves of the other forms. It is found in the fast-flowing streams of east Gippsland.