July 22, 1880] 



NA TURE 



281 



through private subscription, partly through subsidies of the 

 German Government. Among the travellers I may name (i) Dr. 

 M. Buchner, who, starting from San Paolo de Loanda in an 

 easterly direction, may have already reached the large lakes of 

 the Upper Nile or tlie Upper Congo ; (2) Dr. Oscar Lenz, who 

 is on the way from Marocco to Timbuctoo, whence he will 

 proceed to Senegambia ; (3) a large expedition, comprising Dr. 

 Bohm, von Schiiler, De Kayser, &c., which will establish a 

 station near the Tanganyika lake, in connection with the stations 

 of the International Association ; (4) Gerhard Rohlfs and Dr. 

 Stecker will soon proceed to Abyssinia, and thence the latter 

 through the Gallas country to the sea-coast; (S) Dr. Pogge, 

 together with several other travellers, will shortly start from San 

 Paolo de Loanda for the interior, to establish a German station 

 in the neighbourhood of the Muate Tanvo, about in the middle 

 of the Continent ; finally (6) Herr Flegel will follow the course 

 of the Binue upwards, and explore the sources of that river." 

 The German African Society has certainly developed under the 

 presidency of Dr. Nachtigall a very unusual activity, and it is 

 only to be hoped that these great efforts in the interest of the 

 exploration of Africa may have good results. 



The French journal V Exploration has much improved re- 

 cently ; its reports of geographical societies in all parts of the 

 world are specially valuable. Its value would be still greater if 

 it would aim at greater originality, and display more enterprise 

 in the collection of news. It rarely gives any authorities for its 

 numerous notes, thus minimising their value ; and too much 

 space is devoted to the translation of long articles from the 

 Times and other popular sources. This may perhaps render it 

 interesting to the general French public, but greatly detracts 

 from its scientific and international value. However, if it goes 

 on improving in the future as it has done during the last few 

 months, it will ultimately become a really valuable geographical 

 organ. 



The new number of Le Globe coiitains a useful account of 

 geographical work in Central Asia, in 1 878-1 879, contributed 

 by M. Vennikof. 



In view of the present importance of Asterabad, Her Majesty's 

 Consul opportunely gives a brief geographical description of the 

 province. It is situated in the south-east corner of the Caspian 

 Sea ; its inhabitants do not exceed 45,000, and the town can 

 only boast of S,ooo souls. It is bounded on the south by the 

 high range of mountains which separate the Caspian provinces 

 from the other parts of Persia ; on the north it is bounded by 

 the Atrek as far as Chat, at the confluence of that river and the 

 Sombar, while beyond that point the position of the boundary is 

 doubtful. The west is bounded by the Caspian Sea and the 

 province of Mazanderan, and in the east it adjoins the province 

 of Meshed. Gez, Molla Xelle and Gumush Teppe are the only 

 ports in use. The province is well-wooded, and is watered by 

 numerous mountain streams. Its inhabitants belong to the 

 Kajar tribe, of which the Shah is the personal head. The 

 fertility of the 'soil is great, and the timber in the forests is 

 magnificent, but unfortunately there are no roads worthy Of the 

 name. 



M. BouTHiLLiER DE BEAUMONT, the President of the 

 Geneva Geographical Society, has just published a pamphlet 

 entitled Shoix dUin j\lh-idien Initial Unique, 



The Colonies and India publishes an interesting summary of 

 a plan which Mr. G. J. Morrison, the engineer of the short-lived 

 Woosung railway, has sketched for the restoration of the Grand 

 Canal, which at present is usually impassable in places. The 

 essential point in his scheme is the substitution of proper locks 

 for the wasteful sluices now in use, with of course more extensive 

 works at the crossing of the Yellow River. 



The same paper states that the Legislative Assembly of the 

 Transvaal has before it a measure providing for a trigonometrical 

 and geological survey of the country, in the course of which it is 

 expected that abundant mineral wealth will be proved to exist 

 in the colony. 



On July 13, at the end of the French legislative session, the 

 Minister of ^Iarine and the Colonies presented to the Lower 

 House a credit of 1,300,000 francs for establishing fortified 

 posts from Medina on the Senegal to Bafoulabe on the Niger, 

 on the route which will be followed by the projected railway fot 

 connecting these two large rivers. It includes also several 

 other items connected with the same scheme. It was adopted 

 on the same day and voted by the Senate on the iSth, so that 



the first step may be said to have been taken for the establish- 

 ment of the connecting link between Algiers and St. Louis, via 

 Timbuctoo. 



PLANTS OF THE COAL-MEASURES ' 

 "XJX RENAULT has recently published a memoir, in which he 

 ^^'- ' reproduces the views of M. Brongniart respecting the 

 relations which theLepidodendra bear to the Sigillaria;, still 

 insisting that the former are cryptogamic Lycopods, whilst the 

 latter are exogenous Gymnosperms. In endeavouring to esta- 

 blish this position, the French pateo-botanist concludes that if 

 the exogenous Diploxyloid stems (i.e., Sigillarian ones) are but 

 matured states of some Lepidodendra, every Sigillarian type of 

 organisation ought to be found in a young or Lepidodendroid 

 form, because, he contends, the type of the central organisation, 

 once established, undergoes no further change with advancing 

 age. In support of his position he affirms that there are three 

 such Sigillarian types, viz. (1) Sigillaria vascularis, (2) Diploxyloid 

 stems, (3) Favularia and Leiodennaria. At present he contends 

 that only the second of these forms has been discovered in 

 Lepidodendron Harcourtii. He further believes that there are three 

 types ol Lepidodendron known, represented by (i) L. rhodu- 

 mense, with a solid central vascular axis, in which the vessels 

 are not intermingled with medullary cells ; (2) by L. Harcourtii, 

 in which the vascular axis is a cylinder surrounding a cellular 

 medulla ; and (3) an undescribed plant, which he names L. 

 ytitieri, in which the vascular cylinder is broken up into detached 

 bundles of vessels. 



The author of the present paper considers that the above con- 

 clusions are not in accordance with the facts, and he proceeds to 

 give his reasons for this conclusion by demonstrating that^ we 

 certainly have few of the three supposed Sigillarian types repre- 

 sented in a young or Lepidodendroid state : the first by Lepido- 

 dendron vasculare of Binney, and the second by L. Harcourtii, 

 whilst, judging from JL Renault's own description, the L. Jutieri 

 represents the third type. On the other hand, the author believes 

 that of M. Renault's three Lepidodendroid types the first is only 

 a young state of the second, as illustrated by the development of 

 the Burntisland and Arran Lepidodendra described in previous 

 memoirs, whilst the able Frenchman appears not to have been 

 acquainted with the existence of the very characteristic type of 

 the L. vasculare of Binney. 



The author gives the series of facts upon which his opinions 

 are based by tracing the history of the development, first, of 

 Lepidodendron Selaginoides, the L. vasculare of Binney, and 

 second, of L. Harcourtii. 



Commencing with the declaration that the Lepidodendron 

 vasculare of Mr. Binney is but the young state of the Sigillaria 

 vascularis of the same author, he proceeds to show the successive 

 stages by which the vasculo-cellular medullary axis of the former 

 becomes not only inclosed within the exogenous cyUnder of the 

 latter, but that this cylinder ultimately develops into a very con- 

 spicuous example of the Diploxyloid form of stem. The growth 

 of the exogenous cylinder begins at one point of the periphery of 

 the vasculo-meduUary axis, from which point it extends both 

 laterally and radially. The exogenous growth thus first appears 

 in the transverse section of the Lepidodendroid twig as a small 

 crescent, thickest at its centre, but whose two horns creep 

 gradually round the medullary axis, its constituent vascular 

 wedges also growing radially as the lateral growth advances, 

 .until at length the exogenous zone forms a complete ring, inclos- 

 ing the vasculo-medullary axis, in which state it becomes the 

 Sigillaria vascularis of Mr. Binney and M. Renault. The 

 various stages of this growth are represented in the plates, in 

 addition to which a section is described and figured of a branch 

 about to dichotomise, in which process the vasculo-medullary 

 axis has divided into two equal halves, one being destined for 

 each branch. One of these halves of the vasculo-medullary axis 

 displays, with the utmost distinctness, the characteristic crescentic 

 commencement of an exogenous zone, whilst the other half re- 

 tains its primary non-exogenous state. The latter condition thus 

 belongs to the Lepidodendron vasculare of Binney, whilst the 

 former as clearly represents the Sigillaria vascularis of the same 

 author, and the Sigillarian character of which is recognised by 

 M. Renault. We thus have in one stem two branches, one of 

 which, according to the views of the French savant, is a Crypto- 



" On the Org.-inisation of the Fossil Plants of the Coal-measures. Part 

 XI." Paper read at the Royal Society by W. C. Williamson, F.R.S., 

 Professor of Botany in the Owens College, Manchester. Revised by the 

 Author. 



