Peb. 8, 1 872 J 



NATURE 



295 



cases sufficient data existed on which to found a judg 

 ment. He agreed wi(h Dr. Carpenter as to the existenc 

 of extreme modifications, and it had been hi? object to ignore 

 such as seem due to ordinary and local causes, and to group the 

 for.ii'i in accordance with certain characteristics. Wtiether ih-- 

 classification was right or wrong, it was necessary, for the sake 

 of increasing knowledge, that fossils of this kind should be ar- 

 ranged in groups ; and whether these were to be regarded as 

 truly generic was a minor consideration. In forming their types 

 and subtypes the authors had carefully avoided minor differences; 

 but they still thought that the modifications which were capable 

 of being substantiated were significant of a great lapse of time. 

 A variation once established never returned completely to the 

 original type. In Globigeri)ta, he stated that there were in Cre- 

 taceous times 8 forms, in Tertiary 12, at the present time 

 14 ; and these modifications he regarded as equivalent to the 

 specific changes in higher animals. — (2.) "On the Infrilias in 

 Yorkshire," by the Rev. J. F. Blake. The Infralias, i.e., the 

 zones of Ammonites planorbis and Am. ang'ulatus, have been 

 recorded hitherto only from Redcar, to the beds at which place 

 the author referred ; but the chief object of the paper was to 

 describe some secions at Cliff, near Market Weighton, where 

 these and lower beds are well exposed, and have yielded a numer- 

 ous suite of fossils. He considered, however, that these beds 

 did not belong to the typical Yorkshire area, but were the thin 

 end of the series which stretches across England. He supposed 

 there had been a barrier in Carboniferous times, which had sepa- 

 rated the coal-fields of Yorkshire and Durham, prevented the 

 continuity of the Permian beds, and curved round the secondary 

 rocks to the north of it, to form the real Yorkshire basin, while 

 these beds at Clitf were immediately to the south of it. The 

 sections described were six in number, the first pit yielding the 

 great majority of the fossils, and the third showing best the 

 succession of the beds. The fossils could be mostly identified 

 with known forms, and showed a striking similarity to the Het- 

 tanjian fauna. In all the clais of the Infralias Koraminifera 

 were numerous and varied. The section in nit No. 3 shjwed, 

 commencing at the top : — I Stone bed with Am. ai/^n/a/ns (the 

 fossiliferous bed of pit No. I). 2. Thick clays, wiih bands ol 

 stone characterised by Am. Johnstoiti. 3 One band of clay 

 with Ain. flanoi-bis. 4. Thin-bedded stones and clays, some of 

 them oystcr-liaiids. 5. Clavs without Foramintfera, and with 

 impressions of Analina (Wnite Lias). The Avicula contorta 

 scries IS not readied, nor are there any signs of the b me-bed, is 

 the junction with the Kcuper marls, which are found three miles 

 off, is not seen. The paper was full >wed by reference^ to the 

 fo-^sls meiiti med, including the description of those that are 

 considered ncv. Prof Duncan remarked ihit English geologists 

 had been backward in receiving the term Infralias, which he ha 1 

 suggested with respect to the Sutton Down beds some years ago, 

 and the propriety of which was shown by the term having been 

 applied to tne same beds by Fren. h geologists at a still earlier 

 period. As to the Whi'e Lias, he regarded it as a mere local 

 deposit, not to be found out of England. He traced the exist- 

 ence of the Infralias frum Luxembourg through France into 

 South Wales, where corals were abandant. In Yoikshire, 

 th<iug'i one fine coral had been found, the Ammonites seemed to 

 point to a difference in condi ion. Mr. Hughes remarked that 

 the lithological character of the beds, as described by the author, 

 did not agree with that of the Iniralias in the S \V. of England 

 or the N. of Italy, and that the palceont'ilogical evidence which 

 had been laid before the Society did not confirm the view that 

 they Were Infr.dias, the author having especiilly noticed the 

 absence of Avifiila contorta where he expected that it should 

 occur. Also, by reference to the author's section, Mr. Hughes 

 pointed out tint below what he described as Infralias he drew 

 other beds which were not Trias, the author having explained 

 that some beds which had been called Trias were only stained 

 beds of Liassic age. —The Rev. J. F. Blake, in reply, acknow- 

 ledged the difference between the Yorkshire section and those of 

 the neighbourhood of Bath, but insisted on the similarity of the 

 fossils. 



Linnean Soci;ty, February i.— Dr. J. D. Hooker, F.R.S., 

 vice-president, in the chair. "On the Classification and Dis- 

 tribution of Composite," by G. Bentham, I'.R.S., president. 

 The order Composita:, or Synantherce, is remarka >le, not only 

 from its enormous size, but from its extremely natural and well- 

 marked characters, there being not a single instance in which it 

 is doubtful whether a plant should be referred to this order or 

 not. AU the essential characters of the andrcecium, pistil, 



structure of the fruit, structure of the seed, and inflorescence are 

 ab^iilutely constant throughout the 10,000 species comprised 

 within it. This very fact, however, renders its sub-division into 

 tribes and genera a matter of extreme difficulty, the systematist 

 being compelled to adopt characters as generic, which, in other 

 orders, would hardly be considered as even specific. After 

 oriefly reviewing the labours of Linna;u3, Jussieu, Cassini, Don, 

 Lessing, Schultz Bipontinus, De CandoUe, Asa Gray, Hildebrand, 

 Delpino, and other botanists who have paid special attention to 

 this subject, the author spoke of the special opportunities he had 

 had in the preparation of the "Genera Plantarum," in conjunc- 

 tion with Dr. Hooker, for examining himself nearly the whole 

 of the genera comprised within the limits of the order, and then 

 proceeded to the consideration of the value of the several 

 characters available for the distinction of genera and tribes : 

 I. Sexual differences in the florets contained in the capitulum, 

 which may either have both the male and the female organs per- 

 fect, or the female organs sterile in the central florets, or the 

 male organs or both sets abortive or wanting in the marginal 

 florets. These distinctions formed the basis of Linnceus's order, 

 but have been considered of less and less importance by subse- 

 quent writers. The author finds them sometimes constant in 

 large genera or subtribes, sometimes variable in closely-allied 

 species. 2. Di- and tri-morphism, very rare in Composita;, except 

 as connected with sexual diflTerences. 3. Differences in the pistil. 

 The ovary and ovule are uniform throughout the order, and the 

 style nearly so when it acts only as the female organ ; but the 

 modifications of its extremity, in so far as they are destined to 

 sweep^ the pollen out of the anther tube, supply some of the 

 most important differential characters for genera, and even for 

 tribes. These characters, first brought forward by Cassini, formed 

 the basis of Lessing's and De CandoUe's classifications, but have 

 in many instances been too implicitly relied upon. 4. Differences 

 in the fruit and its pappus. The structure of the fruit and seed 

 is uniform in the order, but the outer shape of the achene and its 

 ribs, angles, or wings have been made much use of, e pecially by 

 Schultz Bipontinus, and the pappus presents such infinite varia- 

 tions so easily observed that it has been applied to the distinc- 

 tion of innumerable genera often very artificial. 5. Differences 

 in the andrrecium. The male organs are as uniform in their 

 structure, nunber, insertion, and relative position as other 

 essential parts of the flower, but appendages often observed at 

 the base of the anthers, usually called tails, having no apparent 

 function to perform, are, however, so constant in their presence 

 or absence, as to .supply most valuable tribual characters. 

 6. Differences in the corolla, which, though uniform as to 

 essential points in its structure and position, sho*s modifications 

 of the limo or lamina, wh ch are of great importance as distinc- 

 tive characters : (i) the pentamerous bgula of Cichoraceae tnincate 

 at the end with five shirt equal teeth; (2) the regular tubular 

 corolla, either slender and equal to the end, or expanded upwards 

 into an equally toothed or lobed limb ; (3) the bilabiate corolla, 

 in which the two inner lobes forming the inner lip are usually 

 shorter or smaller or more deeply divided than the three outer ; 

 and ( 4) the tr merous ligulate corolla forming the ray of most 

 heterogamous cajjitula, in which the two inner lobes are deficient 

 or rarely represented by minute slender teeth. 7. Differences in 

 the calyx. This organ is so reduced as to supply no characters 

 except such as are derived from the ribs and paopus of the ripe 

 fruit, and are considered under that head. 8. Differences in the 

 ultimate inflorescence and bracts, i.e., in the capitulum, its in- 

 volucre, receptacle, and pales, the modifications of which accjuire 

 a great degree of constancy and consequent importance in the 

 distinction of genera or even of tribes, as might be expected 

 from the increased func'ions imposed upon them by the abor- 

 tion ot the calyx. 9. Differences in foliage. There is no type 

 of foliage in Compositaj which may not be found in several other 

 orders, although the leaves are never compound with articulate 

 leaflets, but the opposition or alternation of the leaves are of great 

 assistance as characters of some of the tribes, differences in habit, 

 stature, and general inflorescence, rarely giving absolute characters 

 excepting where numerous capitula are crowded on a common 

 receptacle into a kind of compound cipitulum. 10. Differences 

 in geographical distribution, which, if considered in as far as it 

 may be attributed to oiigin independently of climatologijal con- 

 siderations and modern colonisations, may be of great use in 

 determining natural genera. In th-; portion of the paper now 

 laid btifore the society and read in abstract the author enters into 

 considerable detail with regard to the above several series of 

 available characters, and concludes with a summary of the 

 thirteen tribes which he has adopted for the "Genera Plantarum," 



