166 



LOWEB EOCF.XE FLORAS OF SOUTHEASTERK NORTH AMERICA. 



only 4 to 5 centimeters in length. The centrtil 

 sinus which separates the two prmcipal lobes 

 is angular or rounded. It is relativelj^ shallow 

 and is 3 to 4.5 centimeters distant from the 

 base of the pinnuJe. 



This robust form is clearly rcferal)le to 

 Lygodium, and it is as clearly distinguished 

 from known forms by the large, broad, bluntly 

 rounded, and not elongati^d lobes, as a rule 

 but two in number. Incomplete matei'ial, 

 wliich appears to b(> assignalile to this species 

 but which can not be identified with certainty, 

 is associated with an upper Wilcox floi-a in 

 western Louisiana. 



The present species may be. distinguished 

 from Lygodium I'aitlfusli Ileer, which occurs 

 m the upper Claiborne, ])y its more robust 

 form, stouter, somewhat more open and less 

 numerously forked veins, and liy its two short 

 and wide lobes. 



A visit to Hilgard's classic locality residted 

 in the collection of abundant fruiting material 

 of this species, thus confirming the transfer of 

 the foliage from Ginkgo to Lygodium. The 

 fertile pimiie are of the palmatum type and 

 form a terminal panicle, but the lamina is 

 much more reduced. Each group of sporangia 

 is pedunculate and is elongated and nariowly 

 lanceolate in outline. The sporangia are 

 solitary and sessile and are borne on alternate 

 veins that branch from the flexuous midrib. 

 There are 30 to 35 sporangia in each spike. 

 Two of the most complete panicles are figured. 

 The spikes are well preserved, and the fossiliza- 

 tion is by ferruginous replacement. Some 

 specimens show the single ovate sporangium 

 beneath the scalelike indusiimi. 



Occurrence. — Ackerman formation. Hurleys, 

 Benton County (formerly part of Tippah 

 County), Miss, (collected by E. W. Hilgard, 

 E. N. Lowe, and E. W. Beny). Deposits of 

 Wilcox age, sees. 22 and 28, T. 13 N., R. 12 

 W., De Soto Parish, La. (collected by E. G. 

 Woodruff and G. C. Matson). 



Collections. — U. S. National Museum; State 

 University, Oxford, Miss. 



Family POLYPODIACEffi. 

 Genus MENIPHYLLOIDES Berry, n. gen. 



P^ems with simple pinnate fronds, the fronds 

 or pinnae ligulate, entire. The venation is of 

 the Drynaria composita tyi)e, but differs from 



previously kno^vn fossil or recent genera of this 

 type in lackuig free venules. The general 

 characters of the genus are those of the type 

 and only known species. 



Memphyi.loides ettixgshau.seni Berry, n. sp. 



Plate XI, figures ^-7. 



Description. — Fronds, or jnnna:' of a pimiate 

 frond, simple, entu-e; lanceolate in general out- 

 line; about 15 to 20 centimeters in length and 

 2 to 3 centimeters in maxunum width, which is 

 midway between the apex and the base. P^rom 

 tlie region of gi'catest width th(>. lamma nar- 

 rows al)()ut equally distad and proximad to 

 the cxt(>nded acummate tij) and the narrowly 

 decurrent base. Texture subcoriaceous. Mar- 

 gins entire for a short distance proximad, 

 above tliis point beset with somewhat ir- 

 regularly spaced, generally close, fine, up- 

 wardly directed, serrate teeth. Midrib filirous, 

 very broad and rather flat, generally curved, 

 becoming attenuated distad. Laterals thin, 

 closely spaced and parallel, al)out 0.67 milli- 

 meter apart; they diverge from the midrib at 

 angles of about 60°, become somewhat more 

 ascending, in both apex and base, and run in a 

 slightly flexuous but generally straight course 

 to the margins, where then" ends are jomed l)y a 

 well-marked marginal vem. The venules di- 

 verge from both sides of the laterals at acute 

 angles and anastomose in a somewhat irregular 

 manner to form o])liqucly elongated areola-. 

 No free veinlets occur within the meshes. 



The venation of this species differs from that 

 of any fossil or recent forms kno^\^l to the 

 WT-iter. It is closest to the form from the 

 Enghsh Eocene (Middle Bagshot = Lutetian) 

 descrilied by Ettingshausen and Gardner as 

 MeniplvyUum elegans,^ but differs in its serrated 

 margin and m lacking free veuffets within the 

 meshes. It is not unlike a number of existing 

 nettcd-veined Polypodiacese, but difi'ers in the 

 irregular character of the areolation and the 

 absence of free endings, thus oombming vena- 

 tion cluiracters of recent species of Acrostichum 

 and Mcniscium. It is represc^nted by consid- 

 erable more or less l)roken material and is 

 named in honor of tlie late Baron Ettingshau- 

 sen, wlio did so much in the elucidation and 

 methods of study of Tertiary floras. 



'(iardner, J. S., and Ettingshausen, C. von, British Koccnc flora, 

 vol. 1, p. 36, pi. 3, figs. 10-M, 1S79. 



