I 



170 



i 



STERILITY. 



Chap. XV1JI. 



Poa and Festuoa, when growing on mountain-pastures, propagate th 



~~,w~, „, ^ uooi A x^xi± Mr. jjx3±iuxu*xu, ^ijlh^l oAuiu»ivei,y uy ouiblets. Kalia 



gives a more curious instance 107 of several American trees, which grow 



in tMck woodSj that th(?y are certainly ^jj 



plentifully in marshes or 



adapted for these stations, yet scarcely ever produce seeds; but wh 



accidentally growing on the outside of the marsh or wood, are load 1 



with seed. The common ivy is found in Northern Sweden and Eussin 



but flowers and fruits only in the southern provinces. The Aeon ' 



calamus extends over a large portion of the globe, but so rarely perfects its 



fruit that this has been seen but by few botanists. 108 The Hypericum 



cahjeinum, which propagates itself so freely in our shrubberies by rhizomas 



and is naturalised in Ireland, blossoms profusely, but sets no seed- nor 



did it set any when fertilised in my garden by pollen from plants growing 



at a distance. The Lysimaclvia nummularia, which is furnished with lone 



runners, so seldom produces seed-capsules, that Prof. Decaisne, 109 who has 



especially attended to this plant, has never seen it in fruit. The C 



riijida often fails to perfect its seed in Scotland, Lapland, Greenland, 



Germany, and New Hampshire in the United States. 110 The periwinkle 



( Vinca minor), which spreads largely by runners, is said scarcely ever to 



produce fruit in England; 111 but this plant requires insect-aid for its 



fertilisation, and the proper insects may be absent or rare. The Jussim 



grandiflora has become naturalised in Southern France, and has spread by 



its rhizomas so extensively as to impede the navigation of the waters, 



but never produces fertile seed. 112 The horse-radish (Cochlearia armoracia) 



spreads pertinaciously and is naturalised in various parts of Europe; 



though it bears flowers, these rarely produce capsules : Professor Caspary 



also informs me that he has watched this plant since 1851, but has never 



seen its fruit ; nor is this surprising, as he finds scarcely a grain of good 



^ m ■ Mi — 



arex 



pollen. 



fi 



bears seed in England, France, or Switzerland ; but in 1863 I observed 

 seeds on several plants growing near my house. According to M. Chatin, 

 there are two forms of this Eanunculus ; and it is the bulbiferous form 

 which does not yield seed from producing no pollen. 113 Other cases analo- 



X. 



107 < Travels in North America,' Eng. "2 q pi anc h n, ' Flora de Mont- 

 translat., vol. iii. p. 175. pellier,' 1864, p. 20. 



108 With respect to the ivy and »3 On the non-production of seeds in 

 Icorus, see Dr. Bromfield in the ' Phy- England, see Mr. Crocker, in ' Gar- 



tologist,' vol. iii. p. 376. See also dener's Weekly Magazine,' 1852, p. 70; 



Lindley and Vaucher on the Acorus. Vaucher, ' Hist. Phys. Plantes d'Eu- 



109 ' Annal. des Sc. Nat.,' 3rd series, rope,' torn . i. p. 33 ; Lecoq, ' Geograph. 

 Zool., torn. iv. p. 280. Prof. Decaisne Bot. de l'Europe,' torn. iv. p. 46G; Dr- 



refers also to analogous cases with 

 mosses and lichens near Paris. 



D. Clos, in 'Annal. des Sc. Nat.,' 3rd 



series, Bot., torn, xvii., 1852, p. 129 : this 



no ]vi r> Tuckermann, in Silliman's latter author refers to other analogous 



' American Journal of Science,' vol. xlv. cases. On the non-production of pollen 



1- by this Eanunculus see Chatin, m 



111 Sir J. E. Smith, 'English Flora,' * Comptes Eendus,' June 11th, 186(1. 



vol. i. p. 339. 







