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Show 88 LIN ARIA VULGARIS. CHAP. III. d seedlm. gs s1 I.g htly exceocled th1e solf-t after a time t~e crosse a little further grown, t~le onges fm·tili od in height. When nearly 3 inches In length, loaves on the !.cO rmer were tTve ryd 'plants were on1 y 2 m· e h es . whilst those on the self-fer I :~o pot beino- too small, only one Owjng to an accident, and to d efl erod. tho crossed plant was plant on each SI· a. e bcr re-w upth oa ns elf-foewr tilised' ono 15 I.n c h os,. OI. af•.l 19~ inches in height, and 100 to 77. LINARIA VULGARIS. . h . t oductory chapter that two It has boon mentioned In t ~ Ind rby me many year. ago from . 1 t were raise . largo bods of thJs p .a~ l nd that thoro was t't consplcu-crosscd and sol~-ferti~Ised so~ s, :noral appearance between the ous difference In hmght afn g ds repeated with Inoro care; Tl t ial was a torwar t d my two lots. . 1e r - f the £rst plants oxporimen o on, . but as this was one o d Seeds wore taken from Wild usual moth od wa s not fo.l lo1w bo · hood and sown I. n poor sm·1 m· I)lants growing in this nmg 1 our d with a not the others F . lants were covere ' fl my garden. IVe p which incessantly visit the owers being loft exposed to tho ?cos, d'ng to H. Miillor, arc the . 1d which accor I b t of this spoCl.o~, ai . is ~xcellont observer romaTks * t a ' as excl usi vo fertilisers. Th th nd is rna turo at tho same . b t een the an ers a d tho stigma hes e w . . . . ssible But so few see s . h elf-fertilisatiOn IS po · . f time with t om, s d ]ants that the pollen and stigm~ o are produced by protecte p I' ttl power of mutual interactiOn. tho same flower seem to have I 0 s cnpsulos forming solid d 1 t bore numerou w Tho expose pan s l wore examined and appeared to spikes. Five of these capsu os d ~d these being counted in . . 1 number of sec s; an t . contain an equa d t b 1G6 The five protected plan s piO-one capsule, wore foun o e . a sulos of which five wore duced altogether only twenty-fiv~ ct:Ose co~taino l an average of Inuch finer than all th~ other~, an ca sule of fift.y-five. So that 23.6 seeds, with a ma~Imum In o:~os" ~n tho oxpoF>ed plants to tho number of seeds In the caps t les on the protected tho average number in tho fines capsu plants was as 100 to 14. l If-fertilised seeds from under Some of the spon tan eo us y so d plants naturally tho not an d some see ds from tho. un. covoro l b tho bees were fcrtili ~d and almost certainly m torero sec ~' c . so th~ t the Rown so para toly in two large pots of tho same SIZ ' * ' Die Tiefruchtung,' &c. P· 27D. CHAP. III. VERBASCUM THAPSUS. 89 two lots of seedlings wore not subjected to any mutual competition. Throe of tho crossed plants when in full flower woro mea. urod, but no care was taken to select tho tallest plants; thoiT heights wore 7fi, 7~, and 6* inches; averaging 7 ·OS in height. Tho tlU'oe tallest of all tho self-fertilised plants weTo then carefully selected, and their heights were 6~-, 5~, and 5~, averaging 5 · 75 in hojght. So that the naturally eros. od plants were to tho spontaneously self-fertilised plants in height, at least as much as 100 to 81. VERBASCUM THAPSUS. The flowers of this plant are frequented by various insects, chiefly by bees, for the sake of the pollen. H. Miillor, however, has shown ('Die Bofruchtung,' &c. p. 277) that V: nigrum secretes minute drops of nectar. The aTrangomont of tho repro· ductivo organs, though not at all complex, favours cross-fertilisation; and even distinct species are often crossed, for a greate~ number ofnatuTally produced· hybrids have been ob erved in this genus than in almost any other.* Nevm'tholoss the present species is perfectly self-fertile, if insects are excluded; for a plant protected by a net was as thickly loaded with fine capsules as tho surrounding uncovered plants. Ve1·bascum lyclmitis is rather less self-fertile, for some protected plants did pnloatn tysi. eld quite so many capsules as the adjoining uncovered Plants of V. thapsus had been raised for a distinct purpose from self-fertilised seeds ; and some flowers on those plants wore again self-fertilised, yielding seed of tho second self-fel'tilised generation; and other .flowers were crossed with pollen from a distinct plant. The seeds thus produced were sown on the opposite sides of four la1·ge pots. They germinated, however, so irregularly (the crossed seedlings generally coming np first) that I was able to save only six pairs of equal ao·e. The e when in full flower were measured, as in the following table (XXV.). We here see that two of the self-fertilised plants exceed in height their cmsscd opponents. Nevertheless the averago height of the six crossed plants is 65 · 34 inches, and that of tho six self-fertilised plants 56· 5 inches; or as 100 to S6. * I l1avc given a striking case of a large number of such hybrids between V. thapsu8 nnd lychnitis found growing wil 1: 'Joumal of Linn. Soc. Bot.' vol. x. p. 151. |
