SCIENTIFIC SUMMARY. 
83 
BOTANY AND VEGETABLE PHYSIOLOGY. 
The Flora of Brazil. — Part 50 of the great work of Martius, continued 
by Eichler, was issued some time since. It is occupied by Mr. Bentham’s 
continuation of the Leguminosce (viz. Sivartziece and Ccesalpinece), in 254 
pages of letter-press, fully illustrated by 66 plates. The Swartziece form 
now only the ultimate tribe of Papilionacece. Among the figures are to 
be found one of Guilandina Bonducella and of a related species, now re- 
duced to Ccesalpinia, of Parkinsonia aculeata, and of Cassia Chamcecrista. 
There are 189 Brazilian species of Cassia , no small part of the genus, the 
much desired monograph of which, prepared more than two years ago by 
Mr. Bentham, is probably now printed. 
The Structure of Lepidodendra and Stigmaria appears to have been very 
fully made out in a paper read before the Royal Society by Professor 
Williamson. In this paper he describes the structure of specimens of 
Lepidodendra selaginoides , and appears to make good the conclusion that it 
has an imperfect exogenous structure. He observes that it has a central 
medullary axis, which is closely surrounded by a second and narrower ring 
also of barred vessels, but of smaller size, and arranged in vertical radiating 
laminae, “ which are separated by short vertical piles of cells believed to be 
medullary rays. In a transverse section the intersected mouths of the 
vessel form radiating lines,” and the structure is pronounced an early type 
of an exogenous cylinder. From this cylinder alone the vascular bundles 
going to the leaves are given off. He describes Stigmaria ( u well-known,” 
he says , (< to be a root of Sigillaria ”) as having “ a cellular pith without any 
trace of a distinct outer zone of medullary vessels such as is universal' 
amongst the Lepidodendra. The pith is immediately surrounded by a thick 
and well-developed ligneous cylinder, which contains two distinct sets of 
primary and secondary medullary rays.” Other facts stated tend to show 
that these plants are of the Lepidodendroid type, and Professor Williamson 
therefore includes the Lepidodendroid and Sigillarian plants in a common 
family, making them, along with the Calamitece , to constitute an Exogenous 
division of the vascular Cryptogams, while the Ferns belong to an Endogenous 
division, u the former uniting the Cryptogams with the Exogens, through 
the Cycadese and other Gymnosperms, and the latter linking them with the 
Endogens through the Palmacese. 
Coccoliths not Animals , hut Plants. — The recent investigations of Mr. 
Henry Carter, F.R.S., would seem to put it beyond doubt that these are 
vegetable organisms. They are what Professor Huxley first thought them 
to be, not what he subsequently supposed in connection with his Bathybius. 
Mr. Carter says, considering that the coccolith is so abundant in the 
Laminarian zone, and so voraciously fed on by the Echinodermata and 
Ascidise ; also that it is so nearly allied to Melobesia calearea y that it forms 
the bed of the Atlantic, and is found fossilised in the chalk, he cannot help 
inferring that it is a vegetable organism which contributes chiefly to form 
the calcareous deposits of the present day as it has done in the past, at all 
events in the chalk. 
Sculpture of Seeds. — Professor Lange, of Copenhagen, has published in 
Botanisk Tidsskrift (in Danish) an interesting paper upon this subject, 
