120 NOTMCES of;new books. 



tral pith, and is itself surrounded by a very broad zone of loose cel- 

 lular tissue, which is traversed by bundles of scalariform vessels 

 passing from the woody axis to the leaves. But M. Corda differs 

 very widely from M. Brongniart in his view of the affinities of this 

 tribe of plants ; he considers them as true Exogens, nearly allied to 

 the Crassulacece, and especially to the shrubby Semperviva of the 

 present world. It appears that this view has been more fully ex- 

 plained in a previous publication, to which he refers; but he does 

 not, in the present work, bring forward any material evidence in 

 support of it, nor does he attempt to answer the arguments (appa- 

 rently very, weighty) which Adolphe Brongniart has urged against 

 it in his admirable paper on Sigillaria elegans. 



2. Sigillariece. — The genera are Sigillaria^ Stigmaria, Rhyti- 

 dophloyos and Myelopitys, — the two latter new. The figures of Si- 

 gillaria elegans are avowedly borrowed from Adolphe Brongniart's 

 paper above-mentioned, but here again our author is widely at va- 

 riance with the illustrious French botanist, respecting the affinities 

 of the plants in question. He believes the Sigillarise to have been 

 succulent Dicotyledons closely allied to the recent Euphorbiee ; and 

 he supports this opinion by a very careful and minute comparison 

 of the whole structure of Sigillaria elegans with that of Euphorbia 

 mammillaris and E. Hystrix. The similarity in many respects is 

 certainly very striking, but there is one important difference : in the 

 Euphorbias the outer part of the ligneous body or axis consists of 

 true woody fibre of the ordinary structure, whereas in the Sigillaria 

 this kind of tissue is entirely wanting, the whole of the ligneous axis 

 being composed of scalariform and porous vessels. It is on account 

 of this uniformity of tissue in the Sigillaria that Adolphe Brongniart 

 has referred it to the class of Gymnospermous Dicotyledons. 



The leaves of the Sigillariee have been hitherto unknown, except 

 in the single instance of S. lepidodendrifolia^ where they are de- 

 scribed and figured by Brongniart. M. Corda has discovered the 

 leaves of S. rhytidolepis (a new species from the coal-mines of Bo- 

 hemia), and describes them as linear, very long and narrow, from 

 one to two feet long and scarcely 1^ line broad, with a prominent 

 rib along the middle. They have much resemblance therefore to 

 the leaves of S. lepidodendrifoliay and to those of some species of 

 Lepidodendron, such as L. acerosum and L. longifolium. In fact, 

 it is very likely that some of the so-called Lepidophylla, which 

 occur very frequently in a detached state in the coal-formation, 

 may be the leaves of Sigillariee. 



In treating of Stigmaria, it is remarkable that our author does not 

 even allude to the theorj^, so much discussed of late in England, of 

 that singular production being merely the root of Sigillaria. He 

 gives the specific name of anahathra to our common Stigmaria, of 

 which the anatomy has been fully illustrated by Lindley, Bron- 

 gniart and others, and which is commonly known as S.Jicoides ; while 

 the latter name is reserved for the plant originally described by 

 Sternberg. The two species differ, as it appears, materially, in the 

 nature of the vessels composing their solid axis ; these, in the Stig- 



