The British Association at Birmingham. 353 
Mr. R. C. Davie discussed the pinna-trace in the Filicales, and 
pointed out that there are two main types of vascular supply to the 
pinnae—(1) the marginal type, occurring generally from leaf-traces 
which have no hooks at their ends; (2) the extramarginal type 
which appears regularly in connexion with leaf-traces possessing 
incurved hooks. The marginal type occurs, however, in Aneimia 
and in some species of Dicksonia in which the leaf-traces have more 
or less hooked ends. Variations of the usual methods of pinna-supply 
appear in Loxsoma Cuuninghami , Ouoclea sensibilis, Hymenopliyllum 
deniissnm and N olhochlcena affinis , suggesting intermediate stages 
between the marginal and extramarginal types; while in some 
species of Pteris and Hypolepis, and in some of the Cyatheaceae, 
there is a combination of marginal and extramarginal types. The 
supply to the ultimate pinnae is always marginal, and the supply to 
the pinnae in the earliest leaves is also marginal. 
Dr. E. de Fraine described a new species of Medullosa from 
the Lower Coal Measures. The specimen consisted of a short 
length of stem surrounded by adherent leaf-bases, and of small size, 
the diameters of the transverse section being only 5 cm. x 1.5 cm., 
including the leaf-bases. The vascular system of the stem consisted 
in the upper sections of three irregularly shaped outer steles, 
roughly triangular in outline ; one of these steles branched during 
the length of stem available, so that the lower sections of the series 
show a ring of four steles. The outer ring of steles encircles a 
small central strand or “ star ring,” which undergoes no change in 
the series and forms the characteristic feature of the fossil. A 
narrow zone of periderm enclosed the vascular tissues of the stem. 
The numerous leaf-traces passed out from the peripheral parts of 
the outer steles. The leaf-bases showed a typical Myeloxylon 
structure with numerous exarch collateral bundles and abundant 
gum-canals, and the hypoderma was of the Myeloxylon Landriotii 
type. In the general structure of the steles and of the leaf-bases, 
and in its histological details, the stem shows a very close 
resemblance to Medullosa anglica. 
Prof. E. C. Jeffrey and Dr. D. H. Scott gave a brief account 
of certain Devonian plants showing structure. The specimens 
were collected in Kentucky and come from the lower part of the 
Upper Devonian, being therefore among the oldest known land- 
plants with their structure preserved. The forms investigated 
include Calamopitys americana, n. sp. (a stem allied to C. annularis 
and remarkable for the tracheid-containing pith and the paired 
leaf-trace bundles in the wood); Kalymma petioles (doubtless 
belonging to Calamopitys americana or allied species); Calamopteris 
Hippocrepis n. sp. (a petiole of the Kalymma group but with the 
bundles arranged in a horse-shoe form and largely fused); Archceo- 
pitys Eastmani n. gen. et sp. (a stem with dense secondary wood 
and numerous small mesarch strands of xylem scattered in the 
pith—probably one of the Cordaitales, allied to Pitys ) ; Periastron 
perfoliatum n. sp. (a curious petiole with a median row of separate 
vascular bundles and large lacunae in the ground tissue—allied to 
P. reticulation Unger hut whether a Pteridosperm or a Fern remains 
uncertain); Stereopteris annularis n. gen. et sp. (a petiole with a 
