FROM THE SECONDARY ROCKS OF BRITAIN. 697 



appears to be greater in the lower portions of the stem, and in stems belonging to old 

 plants. These organs, however, are not properly buds; for although they do not appear 

 to hare pushed themselves beyond the permanent bases of the leaves, they are fully 

 developed organs, and differ from the secondary axes of Mcmtellia, which are generally 

 broken off beyond the surfaces of the permanent bases of the petioh , and slum there a 

 woody cylinder agreeing in structure with the principal axis of the plant. 



The secondary axis consists of a very short and slender stem, bearing a aumber <>t* 

 simple linear acuminate leaves. These are the only foliar organs hitherto found con- 

 nected with these fossils 1 . They are composed of oblong eells, all of which are marked 

 with transverse bars, like scalariform tissue (Plate LX. figs. 8 . 10). Large uni-«;mals 

 abound in them; and two vascular bundles run through the leaf, one on either Bide of ite 



median line. The back of the leaf is sparsely clothed with membranaceous scales, like 



the ramentum on the petioles. 



The branch terminates in a fleshy subpyriform enlargement, which bears the s. U. 

 This is composed of, first, a cellular cushion; second, vascular cords supporting the ser<N ; 

 and, third, a mass of irregular cellular tissue enveloping the whole. 



The cushion (Plate LIX. fig. 3) is hemispherical in form, and is constricted at its base. 

 It is composed of thin-walled, roundish cells (Plate LX. fig. 4), passing, a1 Lte upper p< .rt ion, 

 into oblong cells. Everywhere it is penetrated by small isolated vascular bundles < »»- 



posed of fine striated tissue (Plate LX. fig. 5), which rise up from the snrla- - of th ushion 

 When free from the cushion, the cord (Plate LX. figs. 1 & 2) is composed ui ... , „ 

 vascular axis, which is surrounded by a layer of very delicate cellular tone, oUowea bj 

 a covering of larger and thicker-walled cells ; and the cord is invested by a - llular mem- 

 brane composed of a single cell in thickness. These vascular cords, with then- a cm- 

 panying cellular tissue, fill up the lower part of the fruit (Plate IX figs. 1 A i)i a 

 they decrease in size upwards the interspaces are filled in with the cellular tone of h 

 fleshy pericarp. The cords run into the base of the seeds. From the constru ,,n at tl„ 

 base of the cellular cushion a cellular disk is given off, which is developed up* ard 



elopes all the organs that rise above it. It is covered externally vu 1 an < ; ■ 



^uvciupes an xne organs maMiscauv.v .». — inner lav 



formed of a double layer of equal-sized roundish cells (fig. 8). n» ■» . 



This cellular disk, or llcsli\ 



quently penetrates, by a fold, the P«"^^ m especially abundant 



pericarp, is composed of thick- waUedroundxsncen^— ^^ ^ 



the upper portion, where the seeds are buried ; but the; ,aison i ^ ^ f ^ 



vascular cords, and surround and invest the whole structur ^ meciincns I 



branch surround the pericarp, and are closely adpressed to * ^^ 

 have examined, the leaves are imbricated, and bent over on ^i s pi -^ ^ buricd 

 The seeds are confined to the convex upper portion 01 ^"^ its surihcc . Thej 

 in deep pits, and forming a somewhat compact layer mmie 



Lower Gr nsand, in the collet I 



c ^.^ios nf Bennett lies, it 



1 I recently met wi 

 ssils placed bv Mr. I 



Being of the same age as some species 



linear segments 



may belong to this genus. It is a very large leaf, with numer o ^ ^^ ^ ^ off :lt regu i a 



the rachis. The segments are simple on the upper part of the iron , 

 several long and slender ultimate segments. 



