January, 1920] 



PATHOLOGY 



L3 



PALEOBOTANY AND EVOLUTIONARY HISTORY 



E. W. Berry, Editor 



94. Sahni, B. On an Australian specimen of Clepsydropsis. Ann. Bot. 33:81-92. PI. 

 4, 2 fig. 1919. The structure is described of a Clepsydropsis collected in New South Wales in 

 rocks probably of Carboniferous Age. The leaf trace in this genus arose as a closed ring which 

 became flattened and then elepsydroid as a result of a median constriction. Clepsydropsis 

 and Ankyropteris should be united in one genus. The two groups of Zygopterideac, were 

 sharply distinct in regard to habit, the Clepsydroideae having upright stems with radially 

 disposed leaves, and the Dineuroideae creeping rhizomes with leaves confined to the dorsal 

 surface. — W. P. Thompson. 



95. Scott, D. H. On the fertile shoots of Mesoxylon and on allied genus. Ann. Bot. 33 : 

 1-21. PI. IS, fig. 1-3. 1919. — The structure of the fertile shoots of Mesoxylon multirame is 

 described. The important result is that Mesoxylon bore a Cordaianthus in all respects com- 

 parable to the inflorescence of Cordaites. The fertile shoot consists of a flattened main axis, 

 naked below, and bearing distichously arranged bud-like branches lying in the plane of the 

 major axis of the shoot. Each branch bears numerous spirally, arranged bracts, each with a 

 single vascular bundle of mesarc structure. No reproduction organs are attached to the 

 specimens, but the shoots are commonly associated with Mitrospermum (Cardiocarpon) com- 

 pression. The author emphasizes the doubtful nature of the evidence from association but 

 concludes that these seeds probably belonged to the plant. Stems and bud-like shoots are 

 also described which resemble Mesoxylon in all important respects except that the leaf trace 

 is single. They are placed in a new genus, Mesoxy'opsis. — W. P. Thompson. 



PATHOLOGY 



Donald Reddick, Editor 



96. Barker, B. T. P., and C. T. Giningham. Further experiments on the Rhizoctonia 

 disease of asparagus. Ann. Rept. Agric. Hortic. Res. Sta. Univ. Bristol 1917:28-32 [1918]. 

 Continuation of work with soil disinfectants to kill Rhizoctonia violacea var. asparagi (See 



