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Show CHAP. II. IPOMCEA PURPUREA. 36 . . ·sed lants 62·33inches,.oras.100 and that of the SIX self-fertil~xce~ded its antagonist In b.mght. to 75. Every cr~ssed plant on the crossed side was sb ghtly In Pot I. the middle plant d was for a time beaten by inJ·ured whilst young.b y a 1b low ' avne recl t'h e usual supen· on· ty . b t 1 tima te Y reco its opponent, u u d tanoously a vast number more The crossed plants produce stpl?n d pl"nts. and tho capfmlos of Capsules than dI· a the self-fer I Ise . "" ' · 1 · f 3 . 37 seeds whilst t 1oso o · d an average ' the former cont~Ine on 3. 0 or capsule, or as 100 to 89. But the latter contained on~y . 11 p fertilised capsules, those on th~ looking only to the artifiCla dy tai·ned on an avern,ge 4. 46 crossed plan t s aga in crosse cIof-nf ertilised pl::tnts ag::t·i n sel f-seeds, whilst ~hose ~n the a:~ so that the self-fertilised capfertilised contained 4 77. see f th two and of this unusual fact sul es were the more fe. rtile o e ' I can offer no explan::tti?~· Plants of the Sixth Generat1:on.- Crossed and self-fertthsed ' 'th the following result. These were rai.s e d I. n the u sual mann..e ·r ' WllIy eight pl::tnts on each I should st::tte that there w:~~fe~~ri::a became extronloly unside; but as two of the s th . full heio·ht these as wen heal thy and never grew to ncar 1 mr u t of the blisL If they had as their opponents have be~ struc ~: tho avor::tge hei ght of the been retained, they would a vc mtha tl at of the self-fertili sed. t f · ly gTeater an l crossed plan s un au . few other instn,ncos, when I have acted in the same manner In a one of a pair plainly became very unhealthy. T ABL E VII (Sixth Generation.) 1 Crossed rlants. Self-fertilised Plants. No. of Pot. lnchrs. Inches. I. 93 50~ 91 65 79 50 II. ~6~ 87 88 62 IIJ. 87! 64~ Total inches. 525 379 I I · d plants 1S here 87 5, and The average height of the SIX cro~se 0 t 72 This large of the six self-fertilised plants 63 ·16, or as 101 ~ ~specially the difference was chiefly due to most of the p an s, CHAP. II. CROSSED AND SELF-FERTILISED PLANTS. 37 self-fertilised ones, having become unhealthy towards tho close of their growth, and they were severely attacked by aphides. From this cause nothing can be inferred with respect to their relative fertility. In this generation we have the first instance of a self-fertilised plant in Pot II. exceeding (though only by half an inch) its crossed opponent. This victory was fairly won ~fter a long struggle. At first the self-fertiljsed plant was several Inches taller than its opponent, but when the latter was 4~ feet high it had grown eCJ_ual; it then grew a little taller than the self-fertilised plant, but was ultimately beaten by it to the extent of half an inch, as shown in the table. I was so much surprised at this cn,se that I saved t~1e self-fertilised seeds of ~his plant, which I will call the a Hero," and experimented on Its descendants, as will hereafter be described. . . Besides the plants included in Table VII., nine crossed and nine self-fertilised plants of the same lot were raised in two other pots, IV. and V. These pots hn,d been kept in the hothouse, but from want of room were, whilst the plants were young, suddenly moved during very cold weather into the coldest part of the greenhouse. They all suffered greatly, and never quite recovered. After a fortnight only two of the nine self-fertilised seedlings were alive, whilst seven of the crossed survived. The tallest of these latter pbnts when measured was 47 i.n?hes in height, whilst the tallest of the two surviving selffertilised plants was only 32 inches. Here again we see how much more vigorous the crossed plants are than the self-fertiiisecl. Gro.c;sed and self-fertilised Plants of the Seventh Generation.These were raised as heretofore with the following result:- TABLE VIII. (Seventh Generation.) No. of Pot. Crossed Plants. Self-fertilised Plante. Inches. Inches. I. 84~ 74H 84H 84 76 ~ .553 ·- - II. 84~ 65 90 51~ 82~ 80~ III. -- 83 67~ 86 60~ IV. 84g 75~ Total inches. 755•50 614•25 |