48 Parasitical Connection of Lathrai'a Squamdria. 



rated by any absorbing or perspiring pores, the author con- 

 32 tends that their office is 



performed by the papil* 

 lae, and therefore that the 

 imbricated scales are real 

 leaves. " In the case of 

 the LathraeX where they 

 (the leaves) are destined to perform their functions, not 

 only in the dark, but buried in the earth, such an arrange- 

 ment (the general law) would have been inexpedient ; it is 

 therefore substituted by another, admirably adapted to their 

 peculiar circumstances and situation. Had the cuticle been 

 furnished with air valves, the soil would have continually 

 clogged and impeded their ofEce; they are therefore re- 

 moved by a contrivance, as beautiful as wise, and placed 

 within the convoluted chambers excavated for them in the 

 interior of the leaves, where they perform, securely and 

 unseen, their destined office." 



In the course of this able and interesting paper, the author 

 dissents from the general opinion that the sickly colour of 

 this and other parasites is to be attributed to their growing 

 in the shade, as some suppose, or is a consequence of their 

 parasitical condition, as Linnaeus asserts, or of both com- 

 bined; and maintains that the total absence of green arises, 

 at least as much, from their wanting true leaves and a cuticle 

 perforated with absorbing and perspiring pores. To support 

 this view, he instances two parasites of British growth : one 

 of which, C^scuta europse'a, dodder, is destitute of leaves, and 

 has not a tinge of green, though growing in the full light ; 

 while the other, Fiscum album*, mistletoe (perhaps the most 

 strictly parasitical plant we have), is furnished with leaves, 

 and is green. 



* As connected with this subject, and as exciting to further research 

 on the plants adverted to, it may be worth the space here to present 

 a remark which Mr. Bowman expresses in a note at the foot of p. 410. : — 



" I have observed that the mistletoe dies with the tree on which it 

 grows ; and, from a notice in the Magazine of Natural History, vol. ii. 

 p. 294. [by our correspondent L. E. O.], it seems that the Lathrae^a Squa- 

 maria does so too. It has long been doubted whether Listera Nidus avis 

 [Neottia Nidus avis of Swartz] be strictly parasitical. Whatever it may 

 be in the earlier stages of its growth, it certainly is not so in its more 

 advanced state. If it be carefully got up in a clod, and the soil afterward 

 washed from around it, the leaves of the central root or caudex may be 

 seen to terminate in a short curved spur, which tapers to a fine point, and 

 evidently is not attached to any other vegetable. The cuticle of the stem 

 and it bracteas have no perspiring pores." 



