196 



D. H. Scott. 



single clialazal bundle breaks up into about nine strands, which traverse 

 the inner layers of the integument. The upper, free part of the latter, 

 has a complex, chambered structure ; there are usually nine chambers 

 (forming- the '-canopy" of Williamson) each of which receives one of 

 the integumental bundles. The outer layer of the integument has a 

 columnar structure. The free apex of the nucellus is prolonged up- 

 wards through the microp3de, protruding somewhat beyond it, as an 



Fig. 27. Lagenostoma Lomaxi. Apex of seed in median longitudinal section through 

 micropyle. ot. outer part of testa ; r, palisade lajer ; i. t, inner part of testa ; s, ca- 

 vity between testa and nucellus; o, orifice of ])ollen-chamber, ;^c; cc, central column; 

 2)g. pollen-grains; j^h nucellus; mg, megaspore. X about 50. After Oliver. 



open tube (Fig. 27). As in recent Cyeads and in Ginlyo the apex of 

 the nucellus contains the pollen-chamber^), which here has a peculiar 

 form, for the middle of the chamber is occupied by a solid column of 

 tissue, reducing the actual cavity to an annular channel in which the 

 pollen-grains are found (see Figs. 23 cl- 27, and the diagrams in Figs. 

 28 & 29). Within the body of the nucellus is the membrane of the 

 megaspore or embryo-sac. The seed was thus of complex organization 

 and shows that Lyginodendron, in spite of its surviving Fern-like 

 characters, had definitely attained the rank of a typical Spermophyte. 

 The structure of the pedicel indicates that the seed was borne on 

 a foliar organ. The evidence of other species leaves no doubt that 

 the sporophylls were modified fronds or pinnae of compound form, 

 chiefly differing from the sterile foliage in the suppression of the 

 laminae of the leaflets. 



^) First discovered in Cyeads by W. Griffith, Icônes Plant. Asiat., Fart 4, 

 PI. 377 & 378, 1852. Notulae ad Plant. Asiat., pp. 6—8, 1854. Both these works 

 were published posthumously, and Griffith's discovery was made many years 

 earlier. 



