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Show 176 LOBELIA RAMOSA. CHAP, v. sown on th e op POSI.te side's of four pots; but the seedling.s were not su ffi C·i en t l Y thi·nned · Only the tallest plao t on each H.d e \Va. 8 d h fully grown 'Jhe mea~mroments are g1ven m mea~ure , w en · t l1 e prece d1. ng. table · Iu <a- ll four pots the crossed• . plants flower•e •d first. When the seedlings were only about an Inch aLd a half m height both lots were equal. The four tallest crossed plants a:erag?d 19 · 28, and the four tallest self-fertilised 18 · 93 inches In height~ or a.s 100 to 98. S h t there was no difference worth spealnug of betwetn the o t a d 1 · ,, t wo l 0 ts in heiOb 'ht '· though othe. r. ·gre. at a v., anb.tgbe s. are a.e i'IVeu. , as we have seen, from cross-fertlhsatwn. :E rom ewg g1own m pots aud kept in the gretnhouse, none of the plauts J:!roducod any capsules. LOBELIA RAMO SA.* Vm·. Snou;-jlalce. Tho well-adapted means by which cross-fertilisation is ensured in this genus have been described by several authors. t The pistil as it slowly increases in _lon~th _push?.' t.ho pollen out of the conjoined anthers, by the aid of a nng of bn~tlos; tho two lobes of the stigma being at this time closed and In?apablc of fertilisation. The extrusion of the pollen is al. o £w1ed by insects which rub against the little bristles that project from the anthers. The pollen thus pu hed out is carried by i~sects to the older flowers, in which the stigma of tho now freely projecting pistil is open and ready to be fertilised. . I proved the importance of the gaily-coloured corolla, by cuttmg off the large lower petal of several flowers of Lobel~a eriuus ;. anJ these flowers wore neglected by tho hive-bees which were nlCessantly visiting tho other flowers. . A capsule was obtained by crossing a flower of L . rramosa * I have adopted the name given to this plant in the ~ GarM deners' Chronicle,' 1866. Prof. rr. Dyer, however, in~orms . me that it probably is a wh1te vnrwty of L. tenuior of R . .Brown, from W. Australia. t See tho \vorks of Hildebrand and Delpino. Mr. Farrer also has given a remarkably clear description of the mechani ~m by which,~ross-fcl'tili:-.ation it::>efl'ectL d in this genus, in the' Annals u.ud Mag. of Nat. Ili~:;t.' vol. ii. (~th series) 1868, p. 2tHI. In. the all~ed (Yenus Isnturua, the cm·1ous spike ~hich }Jl'Ojcets rc<.:tuugularly from the attthers, and whtch when ~:;lwl:eu causes the poll en to tall on tho back of an entering in~cct, seems to have b, ·on deY.elopeJ. from a bri::>tlr, like oue uf tho~e whieh r:;prino· from the anthers m some uf or :n the species pf Lobcliu, n::; described by l\ir. Funcr. CHAP. v. LOBELIA RAMOSA. 177 wit_h ~ollen from ~n?ther plant, and two other capsules from artrfiCially self-fertilised flowers. The contained seeds were sown on the opposite sides of four pots. Some of the crossed seedlings which came up before the others had to be pulled up and thrown away. Whilst the plants were very small there was not much difference in height between the two lots ; but in Pot III. the self-fertilised were for a time the tallest. When in full flower the tallest_ plant on each side of each pot was measured, and the result 1s shown in the following table. In all four pots a crossed plant :flowered before any one of its opponents. TABLE LXVIII. Lobelia ramosa ( F'irst Generation). No. of Pot. Tallest Crossed Plant Tallest Sdf-fertili scd in each Pot. Plant in each Pot. - Inches. Inches. I. 22~ 17 ~ II. 27~ 24 - -- III. 16a 15 ---- IV. 22 ~ 17 Total in inches. I 89 ·0 70·5 The four tallest crossed plants averaged 22 · 25, and the four tallest self-fertilised 18 · 37 inches in height; or as 100 to 82. I was sur?~ised to find that the authors of a good many of these self-fertilised plants did not cohere and did not contain any polle~; and the anthers even of a very few of the crossed plants were In ~he same condition. Some flowers on the crossed plants were again crossed, four capsules being thus obtained; and some flowers on the self-fertilised plants were ao·ain self-fertilised b ' seven capsules being thus obtained. The seeds from both lots were weighed, and it was calculated that an equal number of capsules would have yielded seed in the proportion by weight of 100 for the crossed to 60 for the self-fertilised capsules. So that the flowers on the crossed plants aO'ajn crossed were much ~o~e. fertile than those on tho solf-fertjlised plants again self- 1ert1hsed. N |