410 MR. B. CLARKE ON THE EMBRYOS OF ENDOGENS. 



Fig. 6. The embryo of Ruppia maritima, the membranous sheath containing the plumule having been 



laid open to show the position of its first and second leaves : a. the smaller lobe of the radicle. 

 FiiT. 7. The embryo oi Zostera marina, showing the smaller lobe of the radicle coiled over the cotyledon 



in its cavity. 

 Fig. 8. The same, opened, and the cotyledon raised out of its cavity : a. the smaller lobe of the radicle. 

 Fig. 9. The same, in longitudinal section, showing the radicle lying in a narrow canal at its base. The 



membranous sheath containing the plumule is opened to show that it is situated on that side of 



the cotyledon which is next the smaller lobe of the radicle, a. 

 Fig. 10. The plumule more magnified, showing that it consists of two leaves : the first leaf, a, is directly 



away from the cotyledon. 

 Fig. 11 . A germinating seed of Eriocaulon septangulare, showing the primary radicle protruding, with a 



small circular portion of testa on its apex. 

 Figs. 12 & 13. The same more advanced, fig. 13 showing the position of the first leaf of the plumule. 

 Fig. 14. The same, showing the commencement of the formation of the first secondary radicle. 

 Fig. 15. The same more advanced, showing that the secondary radicle has broken through the primary, 



and the first leaf of the plumule become elevated on a cauUculus. From the cauliculus another 



secondary radicle has protruded ; it has no coleorhiza, but the surface of the cellular tissue 



divides to allow its escape. 

 Fig. 16. A seed of Arum Dracunculus commencing to germinate, showing that it has no trace of a 



coleorhiza. 

 Fig. 17. The same more advanced, showing a shghtly elevated line marking the base of the cotyledon. 

 Fig. 18. The same more advanced, showing the position of the first leaf of the plumule. 

 Fig. 19. The same more advanced, the cotyledon having been removed to show a circular line at the base 



of the first leaf, similar to that at the base of the cotyledon in fig. 17. 

 Fig. 20. A germinating embryo of Oryza saliva : a. the upper part of the radicle as understood by 



Richard ; b. the smaller lobe of the radicle (the epiblastus of Richard), which has been regarded 



as a second cotyledon ; c. the cotyledon, showing its relation to the upper part of the radicle. 

 Fig. 21. A germinating embryo of Zea Mays: a. the cauliculus; b. the cotyledon as understood by 



Richard, the plumule having been partly drawn out of the fissure to show its position. 

 Fig. 22. The embryo of Zostera nana, showing the aperture for the emission of the radicle, covered by a 



semitransparent membrane. 

 Fig. 23. A germinating embryo of Luzula campestris extracted from the albumen. The stricture in the 



cotyledon is produced by the pressure of the testa after the radicle has protruded. 

 Fig. 24. A germinating embryo oi Butomns umbellatus. 



Fig. 25. The same more advanced: a. part of the cauliculus (not cotyledon) is seen above the radicle. 

 Fig. 26. A germinating embryo of an Iris, extracted from the albumen : a. the sheath of the plumule in 



its earliest stage. 



