478 



Drs. F. W. Oliver and D. H. Scott. 



[Mar. 19, 



described by Williamson;* a third species, the subject of the present 

 note, was left undescribecl by him, though in his MS. catalogue he 

 named it, after its discoverer, Lagenostoma Lomaxi, a name which we 

 here provisionally adopt. This seed occurs in calcareous nodules of 

 the lower Coal-measures, and chiefly at Dulesgate, in Lancashire. 



In general structure the seed L. Lomaxi agrees with L. ovoides. 



It is an orthotropous seed, circular in transverse section, and 

 broadest midway between base and apex. The height of the seed 

 slightly exceeds the diameter, and in general form it may be com- 

 pared with a Jaffa orange. Its height in full-sized specimens is about 

 5 J mm., the diameter at the equator 4^ mm. Many of the specimens 

 that have passed through our hands show signs of having become 

 detached through the agency of a layer of separation and bear a low 

 conical papilla centrally placed at the chalazal end, beneath which the 

 actual layer of abscission was situated. 



In the most general relations of its organisation the seed approaches 

 the Gymnosperm type in that the integument and nucellus are distinct 

 from one another in the apical region only, whilst the body of the 

 seed, which contains the large single macrospore with traces of pro- 

 thallial tissue, shows complete fusion of the integumental and nucellar 

 tissues. But in other respects the seed is remarkable. The free 

 portion of the nucellus which stands above the macrospore is conical 

 in form; its base is about 0*75 mm. across, and its height some- 

 what greater. The tapering apex reaches to the exterior, plugging 

 the micropylar aperture like a cork. The whole of this structure, 

 the " lagenostome " of Williamson, constitutes a pollen-chamber, 

 owing to the separation of the nucellar epidermis from the underlying 

 parenchymatous body of the free part of the nucellus. The pollen- 

 chamber thus has the form of a bell-shaped cleft situated between the 

 persistent epidermis and the central cone of nucellar tissue. Access 

 to the chamber is gained at the apex, which is open, and pollen- 

 grains are found in its lower part. The integument, which is a simple 

 shell where fused with the nucellus, becomes massive and complicated 

 in its free part, which corresponds to the upper fifth of the seed. In this 

 region it is usually composed of nine chambers radially disposed around 

 the micropyle. The existence of these chambers is indicated on the 

 outside surface of the seed by the presence of nine little ridges dis- 

 posed like the rays of a star around the microp3de, but dying out 

 almost at once. These ridges over-lie the partitions of the chambered 

 portion of the integument just as do the stigmatic bands the septa of 

 a poppy capsule. The whole structure from within is like a fluted 

 dome or canopy, the convexities of which correspond to the chambers, 



* "Organisation" Part VIII, ' Phil Trans./ vol. 167, p. 233, figs. 53—75 and 

 "—79, 1877 ; Pare X, ' Phil. Trans.,' Part II, 18S0, p. 517, figs. 61—63. See 

 Oliver, 'JS'ew Phybologist, 5 vol. 1, p. 115, 1902. 



