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Show 96 THUNBERGIA ALATA. CHAP. III. The average height of the crossed plants is here 20 inc:1es, and that of the self-fertilised 17·12; or as 100 to 86. But thJS excess of height by no means gives a fair idea of the vast superiority in vigour of the crossed over the self-fertilised plants. The crossed flowered first and produced thirty flower-stems, whjlst the Flolffertilised produced only fifteen, or half the number., The pots were then bedded out, and the roots probably came out of the holes at the bottom and thus aided their growth. Early in tho following summer the superiority of the crossed plants, owing to their increase by stolons, over the self-fertilised plants was truly wonderful. In Pot I., and it should be remembered that very large pots had been used, the oval clump of crossed plants was 10 by 4~ inches across, with the tallest stem, as yet young, 5! inches in height; whilst the clump of self-fertilised plants, on the opposite side of the same pot, was only 3~ by 2 ~ inches across, with the tallest young stem 4 inches in height. In Pot II., the clump of crossed plants was 18 by 9 inches across, with the tallest young stem 8~ inches in height; whilst the clump of self-fertilised plants on the opposite side of the same pot was 12 by 4~ inches across, with the tallest young stem 6 inches in height. The crossed plants during this season, as during the last, flowered first. Both 1he crossed and self-fertilised plants being left freely exposed to the visits of bees, manifestly produced much more seed than their grand-parents,-the plants of the original clump still growing close by in the same garden, and equally left to the action of the bees. v. ACANTHACEJE.-THUNBERGIA ALATA. It appears from Hildebrand's description(' Bot. Zoitu11g,' 1867, p. 285) that the conspicuous flowers of this plant arc adapted for cross-fertilisation. Seedlings were twice raised from purchased seed; but during the early summer, when first experimented on, they were extremely sterile, many of the anthers containing hardly any pollen. Nevertheless, during tho autumn these same plants spontaneously produced a good many seeds. Twenty-six flowers during the two years were crossed with pollen from a distinct plant, but they yielded only eleven capsules; ancl these contained very few seeds! Twenty-eight flowers were fertilised with pollen from the same flower, and these yielded only ten capsules, which, however, contained rather more seed than the crossed capsules. Eight pairs of CHAP. III. THUNBERGIA ALATA germinating seeds · 97 and exactly half th were planted on opposite sides ;~~~d~d ~heir oppo~e'::'~ss;: :~:h~alf Tthe self-ferti~i~:;ep~~!~~ s Ie young, before the . w~ of the self-fertili 1 opponents wm·e thro wn awayy weTrhe me.a sured ' and thO .i r crossseec 1 very unequally, some both .f e SIX remaining pairs . c plants, being more th;n t . o the crossed and seJf-fe t'gl:ew height of the crossed pl wt we as tall as the othe rs. The r I Iscd fertilised plants 65 i han s was 60 inches, and that of thaverage b t . . nc es, or as 100 t 108 e self- ~isw::s:~,~~~~!e~~!: ual~ here ap;ears ·to ~~r~~s, g~~~~f~re, and growing very unequa~~y e~~~antls in a very sterile conditi: ' wus y cannot be trusted. H |