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Show 126 HETEROSTYLED DIMORPHIC PLANTS. CHAP. III. TABLE 21. Mitchella repens. Nature of Union. Long-styled flowers, by pollen of} short-styled. Legitimate union Long-styled flowers, by own-form} pollen. Illegitimate union . . Short-styled flowers, by pollen of} long-styled. Legitimate union. Number of Pairs of Flowers fer-tilised during the second Season. 9 8 8 9 Number of Average Number of Drupes pro- good Seeds duced during per Drupe in the second all the Drupes Season. during the two Seasons. 8 4·6 --- 3 2·2 7 4·1 0 2·0 Short-styled flo,•.rers, by own-form}j pollen. Illegitimate union . . -------1--------·------- Th~et~':.~ legitimate .uni.ons. to:}j __ 1_7_~-~-~ The two illegitima. te . um.·ons. to·-} /1 17 3 2 . gether 1 It follows from this table that 88 per cent. of the paired flowers of both forms, when legitimately fertilised, yielded double berries, nineteen of which contained on an average 4·4 seeds, with a 1naximum in one of 8 seeds. Of the illegitimately fertilised paired flowers only 18 per cent. yielded berries, six of which contained on an average only 2·1 seeds, with a maximum in one of 4 seeds. Thus ~he two legitimate unions are more fertile than the two illegitimate, according to the proportion of flowers which yielded berries, in the ratio of 100 to 20; and according to the average number of contained seeds as 100 to 47. Three long-sty led and three short-sty led plants were protected under separate nets, and they produced altogether only 8 berries, containing on an average only CHAP. III. BORRERIA. 127 1·5 seed. Some additional berries were produced which contained no seeds. The plants thus treated were therefore excessively sterile, and their slight degree of fertility may be attributed in part to the action of the many individuals of Thrips which haunt d the flowers. Mr. J. Scott infonns me that a single plant (probably a long-styled one), growing in the Botanic Gardens at Edinburgh, which no doubt was freely visited by insects, produced plenty of berries, but how many of them contained seeds was not observed. BORRERIA, NOV. SP. NEAR VALERIANOIDES (RUBIACE..tE ). Fritz Muller sent me seeds of this plant, which is extremely abundant in St. Catharina, in South Brazil; and ten plants were raised, consisting of five longstyled and five short-styled. The pistil of the longstyled flowers projects just beyond the mouth of the corolla, and is thrice as long as that of the shortstyled, and. the divergent stigmas are lik wise rather larger. The anthers in the long-styled form stand low down within the corolla, and are quite hidden. In the short-styled flowers the anthers project just above the mouth of the corolla, and the stigma stands low down within the tube. Considering the great difference in the length of the pistils in the two forms, it is remarkable that the pollen-grains differ v ry little in size, and Fritz Muller was struck with the same fact. In a dry state the grains from the short-sty led flowers could just be perceived to be larger than those from the long-styled, and when both were swollen by immersion in water, the former were to the latter in diameter in the ratio of 100 to 92. In the long-styled flowers beaded hairs almost fill up the mouth of the corolla and project above it ; they therefore stand above the anthers and beneath the stigma. In the |