Hill. — On the Presence of a Parichnos in Recent Plants. 273 
EXPLANATION OF PLATES XIX AND XX. 
Illustrating Mr. Hill’s paper on the Parichnos. 
Abbreviations : — //., ligule ; /., parichnos ; s., sporangium ; s. ;/z., sporogenous mass ; sp., 
sporophyll; t ., trabeculae; v., velum; v. b. vascular bundle; L. S., longitudinal section; T. S., 
transverse section. 
Fig. 1. Isoetes Hystrix. Diagram of T. S. through the base of the sporophyll. 
Fig. 2. Isoetes Hystrix. T. S. through the base of a sporophyll, showing the commencement of 
the mucilaginous degeneration. 
Figs. 3 and 4. Later stages of the same. 
Figs. 5, 6 and 7. Lycopodium clavatum. Series of transverse sections of a sporophyll through 
the region of the sporangium, showing the gradual increase in the mucilaginous degeneration as the 
proximal end of the sporophyll is reached (Fig. 7). The three figures do not represent sections in an 
uninterrupted sequence. 
Fig. 8. Lycopodium clavatum. Part of Fig. 7 more highly magnified. 
Figs. 9, 10 and 11. Lycopodium clavatum. L. S. sporophyll and stem. Parichnos in different 
stages of development. 
Fig. 12. Lycopodium cernuum. T. S. stem, showing foliage-leaves with the parichnos. 
Fig. 1 3. Lycopodium cernuum. L. S. sporophyll, showing dehisced sporangium and the parichnos 
below. 
Fig. 14. Lepidophloios (Will. Coll., 1974 A). Photograph of part of T. S. of leaf. 
Fig. 15. Isoetes Hystrix. Photograph showing many sporophylls in T. S. The parichnos is 
seen in various stages of development. 
Fig. 16. Part of Fig. 14 more highly magnified. 
Fig. 17. Part of Fig. 15 more highly magnified. 
Fig. 18. Lepidodendron. T. S. leaf, showing parichnos. 
