202 FLORA OP LOWEK COAL MEASURES OF MISSOURI. 



LEPIDOPHLOIOS Sternberg, 1825. 



1825. Lepidopkloiosi Sternberg, Flora d. Vorwelt, vol. 1, tent., p. xili. 



1833. Haloida Lindley tiud Uutton, Foss. Flora, vol. ii, p. 14. 



1836. Pachyphlcetis G-oeppert, Foss. Farnikr., p. 468 (pars). 



1838. Zamiten Presl, in Sternberg: Flora d. Vorwelt, vol. ii, fasc. 7-8, p. 105 (pars). 



1855. Gyclocladia Goldeuberg (uon L. and H.), Fl. Sarsep. Foss., vol. i, p. 19. 



1867. LomatopIUoios Corda, Flora d. Vorwelt, p. 17. 



Arborescent lycopods with dichotomous ramification. Stems and 

 branches bearing mncli developed scalehke leaf cushions, at or near whose 

 summit is placed the leaf cicatrice. Leaf cushions imbricated, pedicel-like, 

 upright or deflexed; exposed portion with straight sides or rhomboidal in 

 outline, smooth or carinate; sometimes provided with a small tubercle 

 immediatel)' beneath the leaf cicatrice. Leaf cicatrices transversel)^ oval, 

 rhomboidal or rhomboidal-elongate, lateral angles rounded or acute, upper 

 and lower angles generally rounded, sometimes pointed; within leaf cicatrice 

 are three punctiform cicatricules, of which the central is largest and some- 

 times subtriangular in form. Fructification consisting of cones, stalked (! or 

 sessile), borne on specialized branches which show, when decorticated, spi- 

 rally arranged protuberances (Halonia) ; in corticated condition the Halonial 

 scars rise little above or are on a level with the bark, and are represented 

 by a rosette of deflected leaf cushions. Medulla of delicate cells surrounded 

 by a primary vascular axis composed of scalariform vessels which diminish 

 in size from within outward, exogenous vascular zone only developed in 

 specimens advanced in age; bark consisting of three zones — the innermost 

 of small cells, the middle of larger and irregular dense cells, and the outer 

 composed of narrow, dense, prosenchymatous tissue. 



In his admirable memoir, ^ from which the above generic diagnosis is 

 quoted, Mr. Kidston, after reviewing in a most jjainstaking manner both the 

 literature and many of the specimens of the previous authors, enters into a 

 detailed examination of the British material for the purpose of definitely 

 determining the relations of Lepidophloios, LomatopMoios, and Halonia. As a 

 result of this invaluable study we learn (1) that the Sternbergia pith, 

 originally described as proper to LomatopIUoios, is not org-anically united to 

 the cortex described under the latter name; (2) that Lep>idopMoios and Loma- 



' On Lepidophloios and on the British species of the genus : Trans. Eoy. Soc. Edinb., vol. xxxvii, 

 pt. iii, No. 25, 1893, pp. 529-563, pis. i, ii. 



