I'EKSONALES. 



347 



Thfy diverge from the iiiidrih at angles of about 

 50° and arc relatively straiglit. Tortiaries ob- 

 solete. 



This species, which is rare in my colleelions, 

 is very close to Citharexylon villosum Jacquiii, a 

 small tree of the Florida Keys, Bahamas, and 

 ^Viitilles, difl'erini;; merely ill the more numer- 

 ous, straighter, and less ascending secondaries 

 of the fossil form. The genus Citharexylon 

 uicludes more than a score of species eonlined 

 to tropical AmcM'ica, where they are distril)ut(Hl 

 through the West Indies to southern Mexico, 

 Lower California, Bolivia, and Brazil. One or 

 two species have been doubtfully recorded 

 from the European Miocene. 



Occurrence. — Holl}^ Springs sand, Holly 

 Springs, Marshall County, Miss, (collected by 

 E. W. Berry). Grenada formation, Grenada, 

 Grenada County, Miss, (collected by E. X. 

 Lowe and E. W. Berry). 



Collection. — U. S. National Museum. 



Genus AVICENNI.4 Linne. 



AVICENNIA EOCEXICA BciTy, U. sp. 

 Plate CIV, figure 6. 



Description. — Fruit capsular, ovate, ami 

 slightly ol)lique in outline, widest in the median 

 portion and narrowing almost equally in both 

 directions, truncate proximad, shortly apicu- 

 latc distad, greatly compressed. Length 2.7 

 centimeters. Maximum width 1.35 centime- 

 ters. Pericarp thin, coriaceous, feebly ridged 

 with two or thi'ee slight longitudinal eleva- 

 tions, longitudinally striated. 



The identification of the present fonn with 

 the capsule of Avicemiia is not conclusively 

 proved, although the resemblance between the 

 fossil and a smgle valve of the tardily deliiscent 

 capsule of such a modern form as Avicennia 

 nitida Jacquin amounts as nearly to proof as 

 is possible with detached parts of fossil vegeta- 

 tion, especially as Avicennia-like leaves are 

 also present at this horizon. This form is 

 slightly smaller and more nearly symmetric 

 than a valve of a capsule of tiie ])lacl< man- 

 grove; otherwise the resemlslance is complete. 

 It is possible that the Wilcox species of Citha- 

 rexylon based on foliage may be the foliage of 

 Avicennia eocenica, although the form appears 

 to be more closely allied with Citharcxj-lon. 



The genus Avicennia includes a])out .'50 exist- 

 ing species widely distributed on the muddy 



tidal sliores of the Tropics of both licmi- 

 spheres. 



Occurrence. — Lagrange formation (in beds of 

 Wilcox age^i, Pnryear, Henry County, Tenn. 

 (collected l)y I'l. W. li(>rry). 



Collection. — U. S. National MusiMim. 



Avicennia nitidafoumis Bcitv, n. sp. 



Plato evil, figure 4. 



Description. — Leaves medium sized, lanceo- 

 late, in g(Mieral outline and as a rule soniewiiat 

 falcati^ and consecinently slightly inequilateral, 

 wicU'st, in the mi(hile and tapering to both ends. 

 Apex narrowly rounded. Base cuneate. 

 Lengtli about 8 centimeters; ma.ximuni wicUh 

 at or slightly below the midcUc, about 2.1 centi- 

 meters. Margins entire, in many specimens 

 UTCgularly curved. Texture coriaceous. Pet- 

 iole short and stout. Midrib stout, promi- 

 nent on the lower surface of the leaf. Second- 

 aries stout, somewinit ]u-ominent; nine or ten 

 pairs diverge from tiie midrib at angles be- 

 tween .35° and 40°, ascending with but sliglit 

 curvature close to the margins, where they 

 turn upward rather al)ruptly to join the sec- 

 ondary next above and thus collectively form 

 a pseudoacrodrome marginal vein along each 

 margin. Tcrtiaries immersed in the leaf sub- 

 stance. 



This species is not common in the collec- 

 tions. It may be matched with some of the 

 leaves of the existing Avicennia nitida and in 

 connection with the fruits from Puryear, Tenn., 

 described as Avicennia eocenica, renders the 

 generic determmation reasonably conclusive. 

 What is almost certainly a second fossil occur- 

 rence of Avicennia may be seen in a form from 

 the Tertiary of Colombia, which Engclhardt ' 

 erroneously referred to the myi'taceous genus 

 Jambosa Rumpliius and compared with the 

 oriental Jambosa vulgaris De CandoUe, exten- 

 sively cultivated in tropical South America. 



All the existing species are mhabitants of 

 tidal muddy shores and are cosmopolitan in 

 tropical regions. One species, Avicennia nitida, 

 reaches the Florida coast. Its leaves exhibit 

 considerable variation, l)oth in size and out- 

 line, ranging from small obovate to lanceolate 

 and lanceolate-eUiptical fomis, which may be 

 ' rounded or acuminate distad. Among numer- 



' Engelhardt, Hermann, Sonekenbergische naturf. Gesell. Abh., vol. 

 19, p. 3S, pi. 9, figs. 6, 7, 1895. 



