Mar. 14, 1872] 



NATURE 



395 



whilst numbers of them of exactly equal length are arranged in 

 line? radiating from within outwards. These oblor.g cells often 

 pas5 into a yet more elongated series with somewhat thickened 

 walls, which become almost vascular, constituting a series of 

 basl-fibres. In the transverse sections these prosenchymatous 

 ce Is are always arranged, like the vessels of the ligneous zone, 

 in radiating lines. Yet more e.\tern.al is the sub-epidermal 

 parenchyma passing |into leaves composed of the same kind of 

 tissue. The petioles of , the leaves have been long, if not per- 

 manently, retained in connection with the stem, a character of 

 Corda's genus Loinatophloios. 



Where young twigs branch, the vascular medullary cylinder 

 divides longitudinally into two parts ; the transverse section of 

 this cylinder now resembles two horse-shoes pointing in opposite 

 directions. The break in the continuity of each half of the 

 cylinder occasioned by the division is never closed by new vessels 

 belonging to the cylinder ; but when the stem develops exo- 

 genously, the cambium-layer, from which the new growths 

 originated, has endeavoured to surround these openings in the 

 cylinder, and, by closing them, once more to separate the medul- 

 lary from the cortical tissues. Some beautiful specimens have 

 been obtained, which exhibit these new exogenous layers in 

 process of formation. The vessels of the young layers are not 

 half developed. At first they meander vertically through masses 

 of delicate cellular tissue ; but they soon arrange themselves in 

 regular radiating vessels and cells, becoming mere outward pro- 

 longations of the woody wedges and medullary rays of the older 

 part of the stem. At this stage of their growth, the walls of the 

 vessels are deeply indented by the contiguous cells, as if the 

 plastic Issues of the former had been moulded upon the latter 

 structures. As the new vessels enlarge, the superfluous inter- 

 vening cells disappear, until each medullary ray finally consists of 

 a single vertical pile of from one to a small number of cells, 

 arranged in as many Conifera. The exceptional cases are those 

 where vascular bundles pass outwards to the leaves ; these bundles 

 have protected the contiguous cells above and below them from 

 the pressure of the enlarging ligneous vessels and limited their 

 absorption. Both these and the smaller ordinary rays pass out- 

 wards in horizontal and parallel lines. The evidences of an 

 exogenous mode of growth afforded by these young, half-deve- 

 loped layers of wood is clear and decisive. 



The Burntisland deposits are full of fragments of strobili, es- 

 pecially of toni sporangia and of macrospores. Several fine Zi/Zf/i'- 

 slrohi have been obtained, like those to which the fragments have 

 belonged, and which the author believes to have been the fruits 

 of the stems described. The structure of these strobili is very 

 clear and of interest ; the primary branches from the central axis 

 subdivide, so that each sporangium rests upon a separate bract, 

 from the upper surface of which a vertical lamina arises, and, 

 extending the entire length of the sporangium, ascends far into 

 its interior, where it bifurcates. The cellular walls of the spo- 

 rangium blend with the bract along each side of this sporangio- 

 phore. The microspores occupy the upper part of the Lepido- 

 strobiis, and are usually triplospores, sometimes tetraspores. The 

 macrospores occupy the lowermost sporangia, are of large size, 

 and are very remarkible from having their external surfaces 

 clothed with numerous projecting caudate appendages, each one 

 of which is slightly capitate at its extremity. So far as the 

 aivthor is aware, this is an undescribed form of macrospore. 



Two new lorms of LepiJedciiJron are described from the Old- 

 ham beds, in one of which the medullary axis attains to an un- 

 usually large size, even in the young shoots ; whilst the other is 

 rem ukablc for the magnitude of its leaves. It is obvious that 

 the plant which is tlie chief subject of the memoir is a true 

 example of Corda's genus Diploxyloii, so far as its woody axis is 

 concerned ; whilst its bark and leaves are those of a Loniato- 

 phleios, and its slender twigs are Lcpidodendra. The author also 

 points out the probability that the plant had a true Stigmarian 

 root. 



The structure of these fossil types is compared with that of 

 recent Lycopodiacai. The vascular medullary cylinder is shown 

 to be an aggregation of the foliar vascular bundles, so that the 

 vascular connection between the leaves and the stem is main- 

 tained exclusively by means of these vessels, which thus corre- 

 spond most closely with the central vascular axes of living 

 Lycopods. On the otlier hand, the exogenous layers do not com- 

 municate directly with the leaves in any way ; but, on the other 

 hand, they are homologous with the corresponding layers in the 

 Stigmarian root, in which latter they receive the vascular bundles 

 from the rootlets. The medullary cylmder does not enter the 



roots, but appears to terminate at the base of the stem, though 

 the pith is prolonged through them. Hence it seems probable 

 that the nutritive matters were taken up from the soil by the 

 Stigmarian rootlets, that it ascended into the Diploxyloid stem 

 through the exogenous layer, but that, in order to reach the 

 leaves, if conveyed by the vessels, and not by the cellular tissues, 

 it had to be transferred by endosmosis to those of the medullary 

 cylinder. The bark of the fossil plants is compared with those 

 of Lycopodium chanurcyparissiis, and Sdagiiiella Martensii, which 

 two combined represent the former. 



These discoveries necessitate some changes in generic nomen- 

 clature, since the several parts of the plant not only represent the 

 three genera above mentioned, but also several others. Mean- 

 while some other errors require correction. Corda erroneously 

 defined his genus DiploxYhii as having no medullary rays, and 

 Brongniart relied upon this distinction in separating Diploxyloii 

 {torn. Sigillmia; but no difference exists between the ligneous 

 structures of the two genera, so far as Sigillaria is illustrated by 

 Brongniart's S. liegans. Corda, Brongniart, and King all agree 

 in regarding Diploxyloii (which is identical with Witham's 

 A?ialiathm) as a Gymnospermous Exogen. The necessity for 

 abandoning this separation of the plants in question from the 

 Lycopodiaocr, urged in the author's previous memoir, is now 

 made more obvious than before, the distinctions upon which the 

 great French botanist relied in his classification being now shown 

 to be such as mere differences of age can produce. The author 

 concludes from his own observations that the genera Diploxyloii, 

 Auahathra, Lomatophlows, and Ltptoxyloi! must be united. 

 Brongniart had already brought into one generic group Corda's 

 genera Loinatophloios^ I^eptoxylon, and Calaiiioxylon, Goppert's 

 genus Packyphylliiiii, and Sternberg's genus Lopidopkloios, giving 

 the latter name to the whole. Hence no less than si.\ obsolete 

 generic names are disposed of. The author finally follows 

 Brongniart in adopting the term Ltpidophloios, and temporarily 

 assigns to the plant described the trivial name of L. breziifolium. 

 The further relations of this genus to more ordinary forms of 

 Lepidodciidron require further investigation. 



Linnean Society, March 7. — Mr. G. Bentham, president, 

 in the chair. " Revision of the genera and species of Scilleic" by 

 J. G. Baker. This paper contained technical details of the new 

 groups and genera proposed of this difficult tribe of Liliaceae in 

 continuation of papers already presented to the society. — " On the 

 Andnxcium in Cochliostcma," by Dr. M. T. Masters. In this 

 singular genus of Commelynacece, from the Amazon regKSi, the 

 staminal arrangement is different to anything else observed in the 

 vegetable kingdom. There are three petaloid stamens, all 

 arranged 'on the posterior side of the pistil, within which are 

 three spir.^1 bodies constituting the anthers. Within these are 

 three staminodes, one of which is not developed till a con- 

 siderably later stage than the other two ; they do not appear to 

 have any physiological value. The mode of fertilisation is 

 obscure ; the stamens and styles are both so completely obscured 

 that self-fertilisation seems impossible. — " On a supposed hybrid 

 between Vaccinium Myrtilliis 2mA V. Vitis-Idita," by Mr. Gardner. 

 In the discussion which followed, the prevalent opinion was that 

 the plant was but a variety of V. Vitis-Lliva. — "A list of the 

 Marine Alg.^ of St. Helena," by Dr. Dickie. These are twenty- 

 one in number, all dwarf, and, notwithstanding the remarkable 

 peculiarity of the terrestrial vegetation, only one species is pecu- 

 liar to the island. — " Catalogue oinew Leguminosa from Western 

 India," by N. A. Dalzell. 



Chemical Society, March 7.— Prof. WilUamson, F.R.S., 

 vice-president, in the chair. — In the course of the ordinary 

 business of the society, the proposed changes in the officers 

 and council of the society for the ensuing year were 

 announced. — Dr. Debus, F.R.S., then read a paper "On 

 the reduction of ethylic oxalate by sodium amalgam." In 

 1864 Dr. Friedlander described, as the result of this re- 

 action, the production of the sodium salt of a new acid, 

 which he named glycolinic acid. Although the author has care- 

 fully repeated Dr. Friedlander's experiments, and varied the de- 

 tails of the process indifferent ways, he has been unable to obtain 

 glycolinic acid, the only acids formed being glycoUic and tartaric. 

 A comparison of the crystalline form of a specimen of sodium 

 glycolinate, prepared by Friedlander, with that of sodium glycol- 

 late, would seem to indicate that it is identical with the latter. — 

 Two other papers were read, one "On metastannic acid, and the 

 detection and estimation of tin," by A. H. Allen ; and the other, 

 " Note on the quantity of caesium contained in the water of the 



