. The origin of a land flora, a theory based upon the facts of alternation. Plant morphology. rj. Mr Fig. 260 bis. Ophioglossum vulg-atum, L. 58 = longitudinal section through a young seedling. zci=first root with evident apical cell; _/"=Lhe foot only slightly projecting; e=the epibasal region of the embryo; fi=rudiment of pro- thallus. X35- 6i=larger, three- rooted seedling in longitudinal section ; p=prothallus ; W\=first root; h â entering fungal filament; en=endo- phytic fungus, aiv = insertion of 2nd and 3rd roots; j=apex of rhizome: b\> ^2» 38=leaves; c, c=canal; kl\- A4=sheath
. The origin of a land flora, a theory based upon the facts of alternation. Plant morphology. rj. Mr Fig. 260 bis. Ophioglossum vulg-atum, L. 58 = longitudinal section through a young seedling. zci=first root with evident apical cell; _/"=Lhe foot only slightly projecting; e=the epibasal region of the embryo; fi=rudiment of pro- thallus. X35- 6i=larger, three- rooted seedling in longitudinal section ; p=prothallus ; W\=first root; h â entering fungal filament; en=endo- phytic fungus, aiv = insertion of 2nd and 3rd roots; j=apex of rhizome: b\> ^2» 38=leaves; c, c=canal; kl\- A4=sheath of first leaf; A/2-^2=sheath of second leaf; Als=sheath of third leaf. X35. (After Bruchmann.) --â iff ^â ixr^W' .A "-'--^. in that genus how the different forms are referable to variation of a single type, and it seems probable that the same should be the case also for the embryos of Ophioglossum. In Lycopodium the variants arise through tuberous swellings and delay of root-formation: here the variants arise in relation to the precocity of the root, a feature related in all probability to mycorhizic nutrition. We have seen that the development of the axis is delayed in O. vulgatum, which may be held to be a less specialised type, though still with precocious root: in 0. moluccanum, also, the root emerges early from the prothallus and projects downwards, but the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Bower, F. O. (Frederick Orpen), 1855-1948. London, Macmillan and Co. , Ltd.
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