Sternhergice. 301 



that the pith itself has not been merely dried and cracked trans- 

 versely by the elongation of the stem, as appears to be the case 

 in the Butternut, {Juglans Cinerea,) and some other modern 

 trees; but that it has been condensed into a firm epidermis-like 

 coating and partitions, apparently less destructible than the woody 

 tissue which invested them. In this specimen the process of con- 

 densation has been carried much farther than in that described 

 by Professor Williamson, in which a portion of the unaltered 

 pith remained between the Sternbergia-cast and the wood. It 

 thus more fully explains the possibility of the preservation of such 

 hollow chambered piths, after the disappearance of the wood. 

 It also shows that the coaly coating investing such detached pith 

 casts is not the medullary sheath, properly so called, but the outer 

 part of the condensed pith itself. 



The examination of this specimen having convinced me that 

 the structure of Sternbergiae implies something more than the 

 transverse cracking observed in Juglandaceae, I proceeded to com- 

 pare it with other piths, and especially with that of Gecropia 

 Peltata, a "West Indian tree, of the natural family Artocarpa- 

 cese, a specimen of which was kindly presented to me by Pro- 

 fessor Balfour of Edinburgh, and which I believe has been noticed 

 by Dr. Fleming, in a paper to which I have not had access. This 

 recent stem is two inches in diameter. Its medullary cylinder is 

 three quarters of an inch in diameter, and is lined throughout by 

 a coating of dense whitish pith tissue, one twentieth of an inch in 

 thickness. This condensed pith is of a firm corky texture, and 

 forms a sort of internal bark lining the medullary cavity. With- 

 in this the stem is hollow, but is crossed by arched partitions, 

 convex upward, and distant from each other from | to 1^ inch. 

 These partitions are of the same white corky tissue with the pith 

 lining the cavity ; and on their surfaces, as well as on that of the 

 latter, are small patches of brownish large-celled pith, being the 

 remains of that which has disappeared from the intervening 

 spaces. Each partition corresponds with the upper margin of one 

 of the large triangular leaf scars, arranged in quincuncial order 

 on the surface of the stem. (Fig. 5.) 



Inferring from these appearances that this plant contains 

 two distinct kinds of pith tissue, differing in duration and pro- 

 bably in function, I obtained, for comparison, specimens of 

 living plants of this and allied famihes. In some of these, and 

 especially in a species labelled "Ficus Imperialis," from Ja- 



