HARDWICKE'S SCIENCE-GOSSIP. 



259 



•with its peculiar drifting mode of flight, exactly 

 Tesembling that in which a thistle plume is blown by 

 the wind. The other day I followed what I took to be 

 a drifting plume, for the sake of seeing what species 

 it belonged to, and found it to be a specimen of this 

 species of moth ; so remarkably similar do the two 

 objects appear when in motion. If the intention of the 

 plume moths is to mimic the pappi of the winged 

 seeds, we can understand why these insects do not 

 fold the wings to the body when at rest, but seem to 

 display them to the utmost instead. The fact that 

 (according to Stainton) out of about twenty species of 

 Pterophori larva; of which have their food plant given, 

 no fewer than ten feed on composite plants, or plants 

 bearing plumed seeds, indicates that the resemblance 

 of the winged insects to pappi must also be protective 

 to females when depositing their eggs on plants which 

 produce down, as well as when they are flying. It 

 would be interesting to compare the different kinds 

 -of thistle and other down with the appearance of the 

 various species of ' plumed moths ' which thus appear 

 to mimic them." 



BOTANY. 



Notes on the distribution of the Three 

 •FORMS OF Lythrum Salicaria. — The plants being 

 abundant in this locality, I made it my business to 

 ramble up and down beside the river Cann, on the 

 west of Chelmsford, between that town and Writtle, 

 with a view to ascertain the relative numbers of 

 its three forms, which I found mixed so evenly that it 

 was hardly possible to gather a handful of the 

 iiowers without having them all. It differs much in 

 this respect from some dicecious plants, of which 

 ■each of the two sexes may be found in patches of 

 considerable size, as of Mcrcnrialis percnnis, 

 which spreads considerably under ground. Lythrum 

 salicaria, though equally perennial, seems to have 

 no means of increasing its numbers except by seed, 

 so that every clump of the plant may be regarded 

 as a distinct individual, and as it undoubtedly fer- 

 tilised legitimately by insects waiting on it in a state 

 of nature, each of the three forms would yield seed 

 from which all the forms would spring. So they 

 all grow together, and I found— long styled, 98; 

 short styled, 113; mixed styled, \22.~J0hn Gibbs. 



Spiranthes ^stivalis.— Your correspondent J. 

 Saunders, in a note on the above rare plant, says it 

 did not grow in the spot mentioned in the New 

 Forest guide book when he visited the bog last year. 

 Now, although he thought he covered every square 

 yard of ground, still, at least one square yard must 

 have been left unsearched, for last year my brother 

 and myself, after two hours of that exhilaratin"- 

 pastime, bog-trotting, suddenly came upon six nearly 

 full specimens, apparently all that were there. It 



seems to me a great pity that such botanists as 

 the lady referred to by your correspondent could 

 not confine their energies to less rare plants. I 

 imagine that as the individual who nearly eradicated 

 the plant from its original station a few years ago 

 was severely censured by the New Forest surveyor for 

 so doing, some restraining power could be exercised 

 over the labourers living in the vicinity, if under the 

 "Woods and Forests," which they probably are; 

 so that visitors to the bog could caution persons 

 undertaking such a commission as your correspondent 

 mentions. — Theodore James. 



A NEW POTAMOGETON. — I sent you a few remarks 

 on a new potamogeton, or at least a curious and 

 abnormal form of pond-weed found by me in 

 September of last year in a small pool, on the banks 

 of the Wharfe at Linton near here. I at first took it 

 to be P. pnclotigiis, but, being somewhat uncertain, I 

 showed the plant to Dr. F. A. Lees, who at once 

 said that it was not prrelongus, and who kindly looked 

 through with me his collection and the Botanical 

 works we had at hand, but without finding'a descrip- 

 tion at all corresponding to the plant. A few 

 specimens of the plant were forwarded by Dr. Lees 

 to Professor Babington, who expressed himself dubious 

 about it, but thought it a state of prrelongus. Mr. A. 

 Bennett, to whom specimens were sent, looked through 

 the British and foreign specimens of nitens, perfoliatus 

 and pnilongtis in Herb. British Museum, but found 

 "nothing that matched the plant ;" he, Mr. Bennett, 

 also at Kew, "looked through I\Ir. Watson's, Mr. 

 Borrer's, and the general collection, and a separate 

 collection from North America, but found nothing 

 there like it, and nothing so much like the plant as 

 some U. S. A. and Caithness specimens that he had 

 in his possession, and said that he referred it to 

 P. pcrfobiatics as an extreme form." The leaves are 

 all submerged, alternate, half clasping, entire, pel- 

 lucid, willow-like midrib pink, and then not raised 

 above the surface as in typical perfoliatus with three 

 longitudinal nerves on each side and a few transverse 

 reticulations. In a recent letter from Mr. Bennett, to 

 whom I sent some of this year's plants, he says ' ' the 

 further and better developed specimen of the Linton 

 potamogeton leaves no doubt that I rightly referred 

 it to P. perfoliatus,^^ and however indisposed I am to 

 disagree with so good an authority, still, to my mind, 

 the pink thin midrib, with at the most three or four 

 nerves on each side, and the absence of smaller inter- 

 mediate ones, and the altogether narrower leaves 

 make it a very strongly marked var. of P. pc?-foliatns, 

 if not altogether a different species. Unfortunately, I 

 have not been able as yet to obtain the plant in fruit, 

 as last year only one or two flower buds on very short 

 peduncles were developed, and this year, although it 

 has increased in quantity, I have not found a single 

 plant making an attempt at fruiting. — John Jackson, 

 Wctherley. 



