14 



HARDWICKE'S SCIENCE-GOSSIP. 



crowded with starch granules ; and, after flowering, 

 many of the scales may be found in a half-decomposed 

 state, quite black and exhausted. 



In addition to this function of food-storage, I am 

 inclined to think (but of this I have at present but 

 little evidence), that the epidermal cells of the scales 

 have the power of attaching themselves to any 

 suitable root with which they may come into contact. 

 But although I have searched very diligently, and 

 washed very carefully, I have not yet succeeded in 

 securing any example showing such attachment. 



In the first place, the attachment, if any, is but 

 very slight, and in the next, the soil in which I find 

 the plant is very clayey and difficult to remove ; but, 

 from several specimens I possess, exhibiting an 

 altered or abnormal condition of some few of the 

 epidermal cells, I am strongly of opinion that they 

 possess this power. 



This leads me to the consideration of the mode in 

 which L. squamaria attaches itself to its host. Dr. 

 Trimen, in his very interesting article on " Parasitism 

 of Flowering Plants," in the " Popular Science 

 Review," July, 1873, mentions, "... thick tooth-hkc 

 scales, from the axils of some of which slender rootlets 

 are given off. The observations of Mr. Bowman, in 

 1829, first showed that upon these rootlets were 

 borne the absorbent tubercules. Carefully washing 

 away the soil will show these attached to the rootlets 

 of the supporting plant, and a section through both 

 displays a perforating cone penetrating the bark at 

 least, and, as I am informed by Mr. Stratton, 

 actually pushing its way into the very wood." 



"Without questioning the accuracy of these obser- 

 vations, I must confess that I have been unable, so 

 far, to discover any such rootlets. I have found 

 many rootlets of the host and of other plants — 

 growing near — interwoven, as it were, between the 

 scales and stem ; and when it is considered that the 

 soil in which the plant grows is invariably dense 

 with these rootlets, it is not surprising that they 

 should be found so interwoven. 



The only attachment that I have been able to 

 discover and fix with certainty, is that which the 

 parasite makes to its host, at and near the extremity 

 of its underground stem. Here it seizes upon, and 

 absorbs into itself, the rootlets of its host, the union 

 usually being so complete that it cannot be deter- 

 mined where the one begins or the other leaves off. 

 Not only the parenchyma, but the vascular tissues 

 also unite, so that the one is continuous with the 

 other. Near the end of the stem the number of 

 host-rootlets absorbed is sometimes very great, a 

 thin transverse section frequently showing four or 

 five attachments ; the rootlets seized are sometimes 

 very large. 



It is beyond these attached rootlets that the 

 branching of the underground stem takes place. I 

 have found as many as fourteen branches upon one 

 such stem ; and on none of these have I been able 



to discover any other attachment, with the exception 

 of the doubtful one mentioned in connection with 

 the scales. If, then, this is the only attachment, 

 weight is added to my conclusion that the function 

 of the scales is that of food-storage. 



In a previous paragraph I have mentioned the fact 

 of not having found any extraneous matter in the 

 cavities of fully-developed scales. In several young 

 ones (gathered in 1885 and 1886), I have, however, 

 found the mycelium of a fungus in great abundance, 

 and have been fortunate in getting sections showing the 

 spores of this fungus developing. As these spores 

 are a considerable size (too large to get in after the 

 closing of the cavity), I am of opinion that they are 

 enclosed by the folding back of the leaf. Fig. 11 

 represents a cavity with spores and mycelium en- 

 closed. 



I am not acquainted with L. clandestina, the 

 other European species, or with any other foreign 

 ones ; but it would be interesting to know whether 

 they resemble L. squamaria in the several charac- 

 teristics mentioned, or whether the modification of 

 the scales, if any, is at a different stage. 



With regard to the allied genus Orobanche — O. 

 picris, O. caryophyllaceiT, O. major, and O. minor — 

 the only species of which I have any knowledge — 

 the method of attachment is very similar, the tissues 

 of host and parasite so coalescing that it is very 

 difficult to trace the connection. 



In Cuscuta the haustoria are distinct cells, pene- 

 trating the tissues of the host. So in Pedicularis, 

 Rhinanthus, and Melampyrum ; but in these the 

 attachment is very slight indeed, and quite different 

 from that which obtains in the Orobanchaceae. 



W. T. Haydon. 



Dover. 



RUDIMENTS AND VESTIGES. 



IN an article which appeared in the October 

 issue of Science-Gossip, I remarked that, 

 " In the sense in which the term Rudimentary is 

 repeatedly to be found in ' The Descent of Man ' 

 (i.e. to express the supposed 'vestiges of structures 

 existing in early types'), it is a contradiction to the 

 theory of evolution." 



Your correspondent, Mr. F. G. Fenn, defends Mr. 

 Darwin's use of it, and confidently asserts that there 

 is a "double meaning" for " the word." He gives 

 two explanations, the exact opposite of one another ; 

 the first expressing, " vestiges of structures existing 

 in early types" — i.e. something left behind from a 

 once fully developed organ, at the very end of its 

 existence ; and the second expressing " the fore- 

 shadowings or beginnings of structures in process of 

 devolopment." 



How these two contrary meanings can be given to 

 the same word requires explanation. 



That Mr. Darwin employed the term in the former 



