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Show 170 HETEROSTYLED TRIMORPHIC PLANTS. CHAP. IV. form, the stigmas pass out between the filaments of the longest stamens (as in the short-sty led form of Linum); and they stand rather nearer to the upper anthers than to the lower ones. In the short-styled Fig. 11. '·--.. __ - ---------------------~ ------,______ --------------------------------------------7 Long-styled. Mid-styled. Short-styled. 0XALIS SPECIOSA (with the petals removed). S S S, stigmas. The dotted lines with arrows show which pollen must be carried to the stigmas for legitimate fertilisation. form, the stigmas also pass out between the filaments nearly on a level with the tips of the sepals. The anthers in this latter form and in the mid -sty led rise to the same height as the corresponding stigmas in the other two forms. Owalis Valdiviana.-This species, an inhabitant of the west coast of South America, bears yellow flowers. Hildebrand states that the stigmas of the three forms do not differ in any marked manner, but that the pistil of the short-styled form alone is destitute of hairs. The diameters of the pollen -:grains are as follows :- From the longest stamens of short-styled • , mid-length , , , longest stamens of mid-styled . , shortest , , , mid-length stamens of long-styled • shortest " " Divi;;ions of the Micrometer. . 8 to 9 • 7 " 8 • 8 . 6 • 7 . 6 CHAP. IV. OXALIS VALDIVIANA. 171 Therefore the extreme differ.ence in diameter is as 8 · 5 to 6, or as 100 to 71. The results of Hildebrand's experiments are given in the following table,. ~rawn up in accordance with my usual plan. He fert1hsed each form with pollen from the two sets of anthers of the same flower, and likewise from flowers on distinct plants belonging to the same form; but the effects of these two closely allied kinds of fertilisation dffer so little th~t I have not kept them distinct. TABLE 27. Oxalis Valdiviana (from Ilildeb1·and). - Number Number Number Nature of Union. of of of Flowers 0apsules Seeds per fertilised. produced. Capsule. Long-styled form, by pollen of longest stamens of short-sty led. LegitimateI 28 28 11•9 union • • • • . • • • • . --~-- ------------ Long-styled form, by pollen of longest I stamens of mid- styled. Legitimate 21 21 12·0 union • • • • • • • • • . Long-styled form, by pollen of own and I own-form mid-length stamens. Illegiti- 40 2 5·5 mate union • • • • • • . . -· Long-styled form, by pollen of own and I own-form shortest stamens. Illegiti- 26 0 0 mate union • • • • • . • · - Long-styled form, by pollen of shortest I stamens of short-styled. Illegitimate 16 1 1 union • • • • • • • • • • Long-styled form, by pollen of shortest J stamens of mid-styled. Illegitimate 9 0 0 union. • • . , • • • , . |