BOTANICAL SUBJECT: 



169 



want, and that therefore its roots might be able to help it on by 

 developing, in addition to anchorage, a suction action, which would 

 enable it to obtain from the ground it fixed itself on whatever it 

 could not get from the water. Thus a beginning of root suction 

 would have been exohredpari passic with root anchorage. "We do 

 not know that the disks of seaweeds do not suck up something 

 from the ground on which they are attached. The mistletoe, the 

 dodder, the Loranthus, the Kafflesia, and others evidently suck up 

 a good deal from their foster-parents, although they have no roots, 

 but it would ajDpear that the disks of seaweeds are mainly orcrans 

 of attachment like those of the tendrils of Ampelopsis Veitchii, 

 and others. 



The root or rhizome of the orchid, called Corallorhiza innata, 

 R. Bn., Fig. 45, is another example of a root and stem organ, that is 

 to say, it shows that there is no essential difference between the 

 root and the stem. Fig. 46 shows that the rhizome of Polysi- 



Fig. 45. Corallorhiza itinata, 11. Bu. (Syme's "Brit. Bot.," vol. 9, p. 132). 



Fig. 46. Disks of Polysiphonia rostraia, 

 Sond. ("Han-. Phyc. Austr.," pi. 242). 



Fig. 47. Roots of Caulerpa 

 trifaria, Harv. (pi. 241, O.C). 



phonia rostrata, Sond., instead of roots, has disks, by which it 

 attaches itself to other alga?, while Caulerpa irifaria, Fig. 47, has 

 these same disks split up into root- like fibres. 



