53Q 



NATURE 



[July 24, 191, 



LETTERS TO THE EDITOR. 

 [The Editor does not hold himself responsible for 

 opinions expressed by his correspondents. Neithei 

 can he undertake to return, or to correspond with 

 the writers of, rejected manuscripts intended for 

 this or any other part of Nature. No notice is 

 taken of anonymous communications.] 



" Cheiropleuria bicuspis " (Bl.) Pr. 



Through the influence uf the Rajah of Sarawak 

 and the activity of the director of the museum there, 

 to both of whom my grateful thanks are due, I have 

 recently received an ample supply of specimens, dried 

 and preserved in alcohol, of the uncommon Malayan 

 tern, Cheiropleuria bicuspis (Bl.) Pr. As some con- 

 siderable time must elapse before its details can be 

 worked out, I think it will be well to state briefly 

 certain points of interest in relation to it. 



The creeping rhizome, which is covered with hairs, 

 not scales, bears long petiolate leaves at intervals, 

 which are variable in the form of the lamina. Some, 

 especially those of the smaller plants, have an ovate 

 acuminate outline, others may be two- or three-cusped, 

 or in large plants the number of lobes may be four 

 or five. In these cases there is an obvious bifurcation 

 o) the lamina, a point well shown in Sir W. Hooker's 

 illustration of the species, quoted as Fig. 175 in 

 Engler, u. Prantl., i., 4, p. 337. The relation of the 

 leaf and its venation to that of Dipteris is very 

 marked in the larger examples. There can be no 

 doubt that the nearest affinitv of Cheiropleuria is 

 with the Matonineae. 



The fertile leaves appear to be always simple, and 

 of narrow form. Their lower surface is covered by a 

 dense mass of sporangia and hairs, in an Acrostichoid 

 manner. The sporangia themselves have an oblique 

 annulus, and the various ages of them are intermixed. 



As against these rather advanced characters, the 

 anatomy presents surprising features of simplicity. 

 Til.- rhizome appears in the Bornean specimens to be 

 constantly protostelic, with much parenchyma, not 

 soknostelic, as stated by Christ (" Farnkraiiter," 

 |>. 128). The leaf-trace conies off as a single mesoxylic 

 strand, which soon opens out and becomes semilunar, 

 and then divides into two equal strands. These char- 

 acters indicate, on one hand, a greater similarity 

 to Mertensia in the mature stock than is shown by 

 any Matonioid fern ; on the other an advance on 

 Malonia and Dipteris, both in the anatomical and 

 the soral condition of the leaf. The effect of these 

 facts upon the comparative position will be, on one 

 hand, to strengthen the relation of the Matonioid 

 series to the Gleicheniaceae ; on the other, to illustrate 

 a further step in advance in foliar character than any 

 of Hum show. The relation to Platycerium has been 

 definitely indicated by Diels (" Naturl. Pflanzenfam.," 

 '••.4. P- 33 6 )- It will remain for more detailed in- 

 quiry into the structure and development of both of 

 these genera to show how far Cheiropleuria approaches 

 Platycerium. Conclusions on this point must be de- 

 ferred for the present, though certain facts appear 

 provisionally to support such an alliance. 



F. O. Bower. 



Botanical Department, Universitv of Glasgow 

 July 18. 



Cupriferous Sandstones at Exmouth. 



Observations made last winter upon the litho- 

 logical characters of the Red Marls, with intercalated 

 sandstones, exposed in the cliff-section running east- 

 wards from Exmouth towards Straight Point, dis- 

 closed some interesting facts which may serve to remove 

 doubts as to these rocks having been formed under 

 conditions contemporaneous with, and similar to, those 

 NO. 2282, VOL. 91] 



prevailing during the deposition of the German Roth- 

 tigendes in Permian times. 



The sandstones consist of very smooth and rounded 

 grains of quart/, and what appears to be cornelian, 

 together with copper and manganese, consolidated by 

 a calcareous and dolomitic cement. The copper occurs 

 as a green carbonate derived from the decomposition 

 of minute particles of copper pyrites present in the 

 rock. Vivid green patches and specks of this copper 

 carbonate are very conspicuous on the surfaces of 

 bedding-planes and other places where water has per- 

 colated freely. Mr. F. Southerden, of the University 

 College, Exeter, kindly analysed some of the speci- 

 mens, and an average sample yielded about 1 per 

 cent., and a richer specimen more than 3 per 1 cut., 

 of the carbonate. None was found in any of the 

 marl, nor in the red sandstones of Rodney and 

 Orcombe Points. 



The manganese is very widely distributed, both in 

 the red and the buff sandstones, as minute black 

 specks, frequently rudely dendritic in arrangement, 

 and as films coating the grains of quartz. Occasion- 

 ally large areas become quite black with it. Where 

 copper is present manganese is always present also, 

 but manganese is frequently present without the asso- 

 ciation of copper. 



The grains of quartz composing the bulk of the 

 sandstone are remarkable for their roundii' s^ and 

 smooth surfaces. Much research in reference to sands 

 leads me to believe that they were originally rounded 

 by wind action, and subsequently- polished by water 

 holding finer matter in suspension. The natural dis- 

 integration of this type of sandstone produces a sand 

 which, when sifted by wind and wave on the sea- 

 beach, should be musical, but it was not until May 

 last, after many visits, that I found several very 

 musical patches on the beach between Rodnev and 

 Orcombe Points, and also under the " High Lands 

 of Orcombe." 



In places along the foot of the cliffs the lime in 

 the cliff-springs cements the beach material into solid 

 masses of sandstone and conglomerate, and drv sand, 

 blown from the beach against wet places on the 

 cliff-surfaces, eventually becomes consolidated into 

 great cakes of sandstone for the same reason. 



Cecil Carus- Wilson. 



A Fresh Feature of the Large Larch Saw-fly Outbreak 

 in the Lake District. 



In the Lake District plantations, and elsewhere 

 throughout the country, those interested in the wel- 

 fare of the larch have viewed with no little apprehen- 

 sion, for some time past, the yearly ravages of the 

 large larch saw-fly (Nematus erichsonii). As direct 

 methods of control are out of the question over most 

 of the affected areas, interest has been centred upon 

 those natural agencies which in any way tend to 

 limit the indefinite multiplication of this saw-fly, and 

 it has been recognised that the atmospheric 'condi- 

 tions, several of the common insectivorous birds, 

 voles, certain insects, and parasitic fungus, are all 

 capable of exercising a considerable if variable influ- 

 ence upon the numbers of the pest. To a combination 

 of forces such as these must be attributed such respite 

 as the trees have gained in certain of the infested 

 areas, and in those cases where accurate observation 

 of the facts was possible it was found that cessation 

 of the saw-fly attack coincided with an overwhelming 

 increase in the numbers of one of its insect enemies, 

 an ichneumon, hitherto unknown to science, Mesoleius 

 tenthrediuis. Mor. This parasite, bv eventually 

 accounting; for more than 70 per cent. 'of the larva; 

 within the cocoons, undoubtedly in these instances 

 plaved a very large part in the reduction of the pest. 



As .V. tenthredinis was knoyvn to be present in 



