236 
Notes. 
A NEW PARASITIC DISEASE OF THE JUNCACEAE.—PRELIMINARY 
NOTICE. —The roots of various species of Juncus are subject to the attack of a Myceto- 
zoan parasite, which I propose to call ‘ Sorosphaera JuncV as being allied to 
S. Veronicae. The terminal stages in the life-histories of both these Fungi are 
strikingly similar, the wedge-shaped spores being collected into spherical balls, 
the sorospheres, although in the case of S. Junci many of these balls are of elliptical 
shape, and often merely loosely aggregated masses of spores fill the root-cells. The 
stages of nuclear division in both parasites are also similar. In old infected roots the 
cortical cells are filled with sorospheres and spores, and in those of recent infection 
the cells contain the nucleated amoebae of the parasite, and in some the nuclei may 
be seen collecting in masses previous to spore-formation. The infection of the root 
takes place by the entry of an amoeba into a root-hair and thence into the cortex of 
the root. The roots show r no hypertrophy. This Fungus is in no way related to 
the Eniorrhiza , which has been described by Weber in Bot. Zeit., 1884, as being the 
cause of tubercle-formation in the roots of Juncus bufonius . The latter is doubtless 
one of the Ustilagineae ; its young spores are binucleate, and it infects the root by 
means of conidia which push their way down the root-hairs. I hope shortly to publish 
in detail an investigation into the life-history of Sorosphaera Junci. 
E. J. SCHWARTZ. 
ON MESOXYLON, A NEW GENUS OF CORD AIT ALES.—PRELIMINARY 
NOTE. —The relation of Poroxylon to Cordaites has been recognized ever since 
the discovery of the former genus by Renault, in 1879. The main anatomical 
distinction lies in the presence, in the stem of Poroxylon , of well-marked strands 
of centripetal wood, forming part of the leaf-trace bundles at the margin of the pith; 
the stem of Cordaites , as Renault states, is * absolutely deprived of centripetal wood V 
the leaf-traces only acquiring it on entering the leaf. Another character of importance 
is the usually discoid pith of Cordaites , while that of Poroxylon is continuous, and 
further distinctions are to be found in the denser wood of Cordaites and in the structure 
of the phloem. 
Within the last five years several stems have come to light in the calcareous 
nodules of the Lower Coal-Measures of Lancashire, combining the characters of 
Poroxylon and Cordaites . The object of the present Note is to briefly place these 
observations on record, and to establish a new genus for the fossils in question. The 
generic name Mesoxylon has been chosen, to express the intermediate position of the 
genus. 
One of the species now placed in Mesoxylon has already been shortly described 
by one of us under the provisional name Poroxylon Sutcliffii , 1 2 while others have been 
referred to under Cordaites . 3 It is now proposed to unite these forms, with others 
since discovered, making five species in all, in the genus Mesoxylon . There are 
already indications that further species may shortly have to be added. 
1 Bassin Houiller et Permien d’Autun et d’Epinac. Flore Fossile. II me Partie, 1896, p. 332. 
2 Scott, Studies in Fossil Botany, 2nd edition, 1909, p. 511, Fig. 184. 
3 Loc. cit., p. 526. 
