118 Proceedings of the British Association. 



each other, even in the same corolla, he cautions botanists against trust- 

 ing too much to them as a specific character, with further observations. 

 Still less does this agree with the continental C. epilinum of Weihe, which 

 is described as " simplex, glomerulis ebracteatis, sub 5-floris ;" because 

 the new plant is sometimes branched, has its heads always suhtended by 

 a broad bractea, and each head, when luxuriant, consisting of eight, ten, 

 or twelve flowers. Still, as the specific name is so strikingly character- 

 istic of its habit of growing always on flax, and is indeed as old as 

 Dodonseus and Gerarde, the author contends that it ought to be retain- 

 ed ; and that Weihe's plant (if such an one there be, though he suspects 

 some mistake,) should be named anew, or its character be revised. Mr. 

 Bowman then described the peculiarities in structure of this singular 

 parasite. When it has fixed itself upon the flax, the root and lower 

 part of the stem shrivel up and die away, and a group of little warts or 

 tubercles is produced from the inner surface of the spire between each 

 head, which strike into the flax and extract its juices. This economy 

 places each head nearly in the situation of an independent plant ; so 

 that, if the stem were separated at intervals, each detached portion 

 would continue to flower and to ripen its seed. This view occurred to 

 him, on observing that the stem gradually thickened upwards as it 

 approached each head, and was again reduced to half its diameter imme- 

 diately above it ; each head being thus dependent on its own subordinate 

 system of exhausting suckers. Another beautiful compensation for the 

 loss of the root, and supporting the view just advanced, is found in the 

 succulent nature of the flowers, which are as fleshy as the leaves of the 

 mesembryanthemum tribe, and contain reservoirs of nutriment to insure 

 the ripening of the seed, and supply the deficiency consequent on the 

 desiccation of the flax. The author adverted to the total absence of 

 green colour in the dodder and other parasites, which is generally con- 

 sidered to be owing to their not directly elaborating their juices from the 

 soil. But the misseltoe is green, though truly parasitical. Others sup- 

 pose the want of colour to arise from their growing in the shade, or 

 being destitute of leaves ; but the dodder, though leafless, grows in the 

 full sunshine ; and lathraea has real leaves, though they are buried in 

 the soil, amply furnished with stomata, which line the inner surfaces of 

 cylindrical cells, and are most wonderfully adapted to their anomalous 

 situation. In fact, they are true leaves turned inside out. The real 

 explanation of the absence of green in plants arises, in all cases, from 

 the want of stomata or pores in the cuticle or outer skin ; for these 

 pores are the lungs, and through them alone the atmosphere can be 

 admitted, and chemically decomposed, by the action of light ; some of its 

 ingredients ministering to the support of the plant, and others entering 

 into new combinations to produce that beautiful variety of verdure, 

 which is the usual summer livery of the vegetable world. 



A Paper was then read ' On the Cultivation of the Cotton of Com- 

 merce,' by Major-Gen. Briggs. The objects proposed in this paper 



