PLANTS. 7 



another zone of a similar but denser tissue : the whole inclosed by a cuticle of 

 radiately-disposed parenchyma. Bundles of spiral or striated vessels pass off from the 

 outside of the (?) medullary sheath into the leaves, the collective bases of which, in the 

 form of lozenge-shaped prominences, cover the stem in quincuncial order. 



Bothfodendron, Lepidodendron, and some other forms, characterise the group. 



Genus Lepidodendron, Sternberg. 



Diagnosis. — " Stems dichotomous, covered near their extremities by simple, linear, 

 or lanceolate leaves, inserted upon rhomboidal areolae ; lower part of the stems leafless; 

 areolae (longer than broad) marked near their upper part by a minute scar, which is 

 broader than long, and has three angles, of which the two lateral are acute, the lower 

 obtuse ; the latter sometimes wanting."^ 



The late investigations of Dr. Jos. Hooker on the fructification of Lepidodendron have 

 completely demonstrated its lycopodal character,^ which -had been rendered extremely 

 probable by the previous researches of Lindley, Brongniart, and Morris, particularly by 

 the latter, who, several years since, described and figured the tripartite spores of this 

 genus, discovered by Mr. J. Prestwich in the coal formation of Coal Brook Dale.^ 

 Although the fructification of Lepidodendron agrees very closely with that oi Lycopodiwn, 

 the character of its tissues removes the genus not only from the latter, but favours 

 both genera, being placed in distinct ordinal groups. 



Lepidodendrons, in their foliage and external appearance, evidently bore a striking 

 resemblance to some of our recent coniferous plants ; but these are the only points of 

 agreement, as their tissues and fructification place them in a much lower division of 

 the vegetable kingdom. They may be said to have been gigantic Lycopodales, 

 rivalling in stature and simulating in appearance some of the Conifers of existing 

 forests. 



Lepidodendron (?) 



Lepidodendron, King. Catalogue, p. 5, 1848. 



— Howse. T. N. F. C. vol. i, p. 264, 1848. 



Specimens of Lepidodendron are occasionally found in the Lower New Red Sand- 

 stone Quarry, between Westoe and South Shields. There is one in the Newcastle 

 Museum from this locality ; but it is so imperfect as to render the making out of its 

 specific ^character an impossibility. 



' Fossil Flora, vol. i. 



2 "Remarks on the Structure and Affinities of some Lepidostrobi," by Dr. Jos. Hooker, F.R.S., &c., 

 inserted in the •' Memoirs of the Geological Survey of Great Britain,' &c. vol. ii, part ii, 1848. 

 ^ Transactions of the Geological Society of London, 2d series, vol. v, pi. xxxviii, figs. 8, 9, 10. 



