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Show 144 TROP JEOL UM MINUS. CHAP. v. leaves· the crossed averaged 13 · 46, and the self-fertilised 11· 07 inches' in height, or as 100 to 82. Five months later they were again measured in the same manner, and the results arc given in the preceding table. The seven crossed plants now averaged 22 · 35, and the seven self-fertilised 16 · 62 inches in height, or as 100 to 7 4. But from the great inequality of the several plants, the result is less trustworthy than in most other cases. In Pot II. the two selffertilised plants always had an advantage, except whilst quite young over the two crossed plants. As I wished to ascertain how these plants would behave during a second growth, they were cut down close to the ground whilst growing freely. The crossed plants now showed their superiority in another way, for only one out of the seven waR killed by the operation, whilst throe of the self-fertilised plants never recovered. There was, therefore, no use in keeping any of the plants excepting those in Pots I. and III.; anu in the following year the crossed plants in these two pots showed during their second growth nearly the same relative superiority over the self-fertilised plants as before. TROP lEOLUM MINUS. The flowers are proterandrous, and are manifestly adapted for cross-fertilisation by insects, as shown by Sprengel and Delpino. Twelve flowers on some plants growing out of doors were crossed with pollen from a distinct plant and produced eleven capsules, containing altogether twenty-four good seeds. Eighteen flowers were fertilised with their own pollen ~mel produced only eleven capsules, containing twenty-two good seeds; so that a much larger proportion of the crossed than of the self-fertili~ed flowers produced capsules, and the crossed capsules contained rather more seed than the self-fertilised in the ratio of 100 to 92. The seeds from tho self-fertilised capsules were however the heavier of tho two in the ratio of 100 to 87. Seeds in an equal state of germ'ination were planted on the opposite sides of four pots, but only tho two tallest plants on each Ride of each pot were measured to the tops of their stems. The pots were placed in the greenhouse, and the plants trained up sticks, so that they ascended to an unusual hejght. In three of the pots the crossed plants flowered first, but in the fourth at the same time with the self-fertilised. When the seedlings were between 6 and 7 inches in hoi o·h t tho crossed began to b ' 0HAF. V. LIMNANTHES DOUGLA srr. 14 show a slight ad vantao·e over t . 5 a considerable heiO'ht o th . hheir opponents. When o· 44·43 and th . o e mg t tallest crossed orown to or as' 100 to ;4 eig~~;htallest .self-fertilised plant~la3u7~s3_av~raged . • vv en the1r gr th 4 Inche agam measured as shown . th ow was completed th F>, ' In e following table:- ey were TABLE L. Trop aeo zu m minus No. of Pot. Crossed Plants. I. lnc6.h5e s. Inches. 50 31 45 II. 69 35 42 45 III. 70 5ti~ IV. I 61& 57~ 467·5 I . The er·g h t tallest crossed I Cight tallest St:Jlf-fertir d pants now averaged 58 ·43 d to 79. Ise plants 46 inches in h . ·h ' an the Th eJg t, or as ] 00 lots wehrei hw a.s also a oo· reat di·f ference in th . . • of 8 t c were left uncovered in th e fertih ty of the two and ep ember the capsules from aile greenhouse. On the 17th the~~ seeds counted. The crossed t~: plants were gathered, or as 10~ :~4ber of self-fertilised plan~s ~~~dy~lded 243, whilst · e only 155 seeds ' Several fl LIMN.ANTHES DOUGLASU manner ' b to wers w ere crosseci and self-for·t T . seeds wh. : there was no marked diife ' I~ed In the usual fertilised Ic they yielded. A vast numb renee In the number of were r . cdapsules were also I)roduced edr of spontaneously self-aiSe in fi un er the t S . crossed ve pots f1·om the ab ne · eedlmgs advantaO'were about 3 inches in heio·:ve seeds, and when the be over the self-fertilised. vv.h t they sho:ved a slight en double this height, thu L |
