male cone are the parts homologous to the bracts of the female; that, in fact, the stamens and bracts are the leaves belonging to the main axis of the male and female cones respectively. At the same time I insisted that, as the male cone consists of a single axis with its leaves, it must therefore be considered as a single flower-in opposition to a view taken by Dr Lindley in his " Vegetable Kingdom,” where he holds, that the male cone consists of a number of monandrous naked male flowers, collected about a common axis," and that the "anther is formed of a partially converted scale, analogous to the indurated carpellary scale of the females." I gave my reasons for inclining to believe with Schleiden that the "scales" of our ordinary cones are flattened shoots, and attempted to refute Dr Lindley's arguments in favour of the carpellary hypothesis. In conclusion, I started some doubts as to the correctness of the generally received opinion upon the nature of the so-called ovule, founded upon what was known of the development of the innermost "seedcoat" in Gnetum, and also from some more theoretical considerations as to the signification of the "corpuscula" of the coniferous "ovule." I was unable, however, to solve these doubts. It was not until some weeks after the publication of my observations that I saw Dr Baillon's paper, which had been published a month previously to mine,* and I was very much gratified to find what I had been occupied with clearly elucidated and established upon a satisfactory foundation. It is unnecessary for me to give any resumé of Dr Baillon's observations, as he has himself given a very clear recapitulation of the main results. He has taken exception to Dr Lindley's arguments relative to the nature of the cone scale, on the same grounds, and, I had almost said, in the same words, as myself. The relation of the stamens to the pistils in Pinus and its allies is very remarkable. The monoecious condition in these plants is neither brought about by a mere suppression of parts in homologous or corresponding male and female flowers, as in many monoecious and dioecious plants; nor by a mere replacement, as it were, of pistil by stamens, and vice versâ, as in * Dr Baillon's paper was published in September, mine in October, 1860. the male and female flowers of Salix; but by the following arrangement:-The male and female cones are corresponding or homologous shoots. The stamens are developed upon the main axis of the male cone; the pistils, on the other hand, are developed, not upon the main axis of the cone, but upon tertiary shoots, the "scales" being the secondary shoots axillary to the leaves of the main axis. In the male cone, the secondary and tertiary shoots may be considered as suppressed; while, in the female, the stamens are replaced by bracts. I have brought with me, for your inspection, a very beautiful example of the combination of the female inflorescence with the male flower in Abies nigra. I alluded to this in a note which I appended to my observations on the "bisexual cones," of Abies excelsa. On the lower two-thirds of this cone, the greater number of the bracts are replaced by stamens, which carry the scales or shoots of the female inflorescence in their axils. This curious combination cannot, I think, fail to strike any one reflecting on it with astonishment. I would now make a few remarks upon the constitution of certain abietineous cones, viz., those of Cunninghamia, Araucaria, Dammara, and their allies. Richard held, that in Cunninghamia, both bract and scale are present; in Dammara, the scale only; while he seems to have been uncertain as to the signification of the structure in Araucaria.* Endlicher considers the cones in all three genera as destitute of bracts. What Richard considered to be the scale in Cunninghamia, he terms a transverse torus.t Schleiden holds the "scales" in Araucaria and Dammara (Agathis) to be unprovided with bracts.‡ Lindley also seems to coincide with Endlicher and Schleiden in viewing the cones of Araucaria as bractless, since he appeals to the leaf-like "scales" of these cones in proof of the carpellary nature of the scales in our ordinary Conifers. § *"Amentum ovatum; squamis introrsum unifloris (squamula postica bracteali? veluti destitutis.") Richard, Mém sur les Conifères, &c., p. 87. + Gemmulæ .... toro transverso insertæ. Endlicher, Synopsis Coniferarum, p. 192. .... Schleiden's Principles, Lankester's translation, p. 383. § Lindley, Vegetable Kingdom, p. 227. After careful consideration, I have been led to the firm conviction, that in the cones of all these genera the bracts are well developed, while the true scales are more or less reduced in size, or altogether incorporated with the bracts. In Cunninghamia, the bracts and scales are quite distinguishable, as was pointed out by Richard.* It is hardly necessary here to enter at length in defence of Richard's opinion; the onus, in this instance, certainly lies upon those who would refute it. Endlicher describes the structure in Cunninghamia and Arthrotaxis thus:-"Squamæ gemmuliferæ plurimæ, ebracteata, basi unguiculata insertæ, imbricatæ, supra unguem toro transverso incrassatæ."+ It is evident, however, that an almost similar description might have been applied to the bracts in Abies pectinata, since here, as in Cunninghamia, there is an unguis or claw common to the bract and scale which are united for some distance from their base (compare figs. 1 and 2). In fact, the union, Fig. 1. Bract and scale from cone of Abies pectinata (Silver Fir); outer surface. Female flowers (" ovules ") have been removed. b, Bract; sc, scale; ung, claw common to both bract and scale. Fig. 2. Bract and scale from Cunninghamia sinensis; inner surface. b, sc, and ung, as in fig. 1; c, points whence the female flowers have been removed. (After Richard.) to a greater or less extent, between the base of the bract and that of the scale seems to be of very frequent, if not of universal occurrence in Abies, Pinus, and their allies. * Richard, Mémoires, p. 81. † Endlicher, l. c. pp. 192, 194. i If a cone of Araucaria be examined, it is manifest that the apparent scales of the cone are serially homologous with the leaves of the shoot which the cone terminates. As Dr Lindley has pointed out (Veget. Kingdom, p. 227), these scales "have actually the same structure as the ordinary leaves;" there is, indeed, a gradual transition from the one to the other. Now, under the ordinary view, the difficulty at once arises; since the "scales" of Araucaria are thus the leaves of the main axis of the cone, how can they correspond to the scales of an Abies, which (whatever view be taken of their nature), are certainly not the leaves of the main axis of its cone? This difficulty may, I think, be removed, if we direct our attention to the small scale-like body (figs. 3 and 4, sc), situated Fig. 3. Bract and scale from Araucaria imbricata. b, Bract; sc, scale; P, pistil; o, orifice of pistil. (After Richard.) Fig. 4. Longitudinal section in the mesial plane of bract and scale from a Fig. 5. Diagram showing the supposed constitution of the cone-scale in Arau- near the apex of the apparent-scale in most of the species of Araucaria. This "squamula" is most distinct in those Araucarias termed Eutassa. It is very small in A. imbricata, and is absent in A. brasiliensis.* It is generally regarded as a process or appendage of the "ovule." † This small scale-like body must, I conceive, be regarded as the representative of the conescale of an Abies. We are prepared for its small size, when we consider the relatively small size of the scale in Cunninghamia when compared with the scales of Abies or Pinus, and for its extensive union with the bract by what occurs in Cunninghamia, or Abies pectinata. If this supposition be adopted, the structures in the cone of Araucaria become at once intelligible, and capable of strict comparison with those in our ordinary cones. What have been termed scales in Araucaria should now be considered as bracts, to which the scales proper are extensively adherent. In Dammara the cone is provided with "scales" so-called, each of which gives origin, about or a little below the centre of its inner surface, to a solitary unequally-winged female flower ("ovule"). These scales have, so far as I am aware, been universally considered as true scales desti- Bract (cone-scale) of Dammara tute of bracts. This, I believe, is exactly the reverse of the truth, and on the following grounds :— Fig. 6. australis. b, Bract; p, unequally winged pistil; x, point of attachment of the pistil. 1st, These so-called scales are not placed in leaf-axils. 2d, In the allied genus Araucaria we have the true scale very much reduced in size. Its free portion actually dis called adnate or adherent ovule) may not really be of the nature of an inferior germen; in which case the "carpel " would necessarily be considered as consisting for the most part, if not altogether, of an axial structure. This point, however, can only be determined by examination of the development. * I have not had the opportunity of examining the cones of Araucaria brasiliensis. Through the kindness of Professor Balfour, I have examined a cone of A. (Eutassa) excelsa, from a scale of which I made the section represented in fig. 4. The transition between the leaves of the shoot and the so-called scales (bracts) of the cone is particularly well seen in young specimens. †See Richard, Mémoires, &c., p. 87; also, Endlicher, "Synop. Conif.," p. 184. |