FOSSIL PLANTS OF THE COAL-MEASURES. 321 



All these localities lie fairly close together, the most westerly being 

 more than 1200 miles from Amboyna. 



A. oceanicd. lies very near A. scabra Benth. from British India, 

 and is easily distinguished from other species of the section Ilellenid 

 with a nodding inflorescence, such as J. dccurra Ridley. 



Baron von Hiigel's specimens lead one to suppose that the 

 curvature of the inflorescence becomes more marked as it grows 

 older, being very slight when the buds first begin to open. In 

 cases where the flowers are much crowded the axis of the inflor- 

 escence becomes twisted so as to obscure the h divergence which is 

 present. Such might account for the want of it in Rumphius' 

 figure. — I. H. Burkill, in Proc. Camhriihje Phil. Soc. ix. 93. 



NOTICES OF BOOKS. 



Further Observations on the Onjanization of the Fossil Plants of the 

 Coal- Measures. By W. C. Williamson, LL.D., F.R.S., and 

 D. H. Scott, F.R.S. Part ii. — -The Roots of CaJamites. 

 Part iii. — Lyijinodendron and Heteramjium. [Philosophical 

 Transactions, clxxxvi B. pp. 683-779.] 



After completing nineteen memoirs dealing with the organi- 

 zation of the fossil plants of the Coal-Measures, the late Professor 

 Williamson was fortunate enough to obtain the co-operation of Dr. 

 D. H. Scott in beginning a new series of communications to the 

 Royal Society, extending and revising the work of the earlier con- 

 tributions. In Part i. of the second series, an extremely full account 

 was given of the stems and fructification of the well-known Car- 

 boniferous genus Calamites ; the genus Sphenoplujllum was also dealt 

 Avith in detail, and its autonomous nature clearly demonstrated. 

 In Part ii. our knowledge of the former genus is rendered still more 

 complete. For many years we have been familiar with the existence 

 of root-like appendages to the nodes of calamitean stems ; and 

 comparatively recently, Prof. Renault of Paris proved the identity 

 of the genera Astromijelom and Calamites, the former being simply the 

 root of the latter. In the present memoir the histology of the 

 Calamites root is described with great clearness and completeness, 

 and the organic continuity of stem, roots, and rootlets satisfactorily 

 established. The roots of Calamites differ from the stems in the 

 absence of nodes, the usually solid pith, and the absence of canals 

 accompanying the vascular bundles. At the periphery of the pith, 

 which in the larger specimens is occupied by thin-walled paren- 

 chymatous cells, there occur several groups of primary xylem, 

 showing a distinct centripetal arrangement of the tracheids; each 

 group is triangular in form, with the spiral tracheids of the 

 protoxylem occupying the apex. In a few exceptionally well- 

 preserved sections, groups of primary phloem are seen alternating 

 with the xylem. This typical root-arrangement of the primary 

 xylem and phloem is beautifully shown in one of Mr. Brebner's 



