. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. Fig. .^59.—A, Female prothallium with the ilrst archegonium (ar), X70; B, male pro- thallium, X70. however, the prothallium while still small has a somewhat cy- lindrical body composed of several layers of cells, and in these the rhizoids are mainly confined to the base. The chloroplasts which these at first contain are gradually changed into leuco- plasts, and may be completely absorbed (Buchtien (i), p. 17). A comparison of the gametophyte with that of Lycopodium cernuum has been made (Jeffr
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. Fig. .^59.—A, Female prothallium with the ilrst archegonium (ar), X70; B, male pro- thallium, X70. however, the prothallium while still small has a somewhat cy- lindrical body composed of several layers of cells, and in these the rhizoids are mainly confined to the base. The chloroplasts which these at first contain are gradually changed into leuco- plasts, and may be completely absorbed (Buchtien (i), p. 17). A comparison of the gametophyte with that of Lycopodium cernuum has been made (Jeffrey (2), p. 186), but as Goebel has pointed out ((22), p. 409) there is this radical difference,—in Equisetum the prothallium is dorsi-ventral, as it is in the Ferns, while in Lycopodium it is radially constructed. The more or less evidently upright form assumed by the prothallium in Equisetum is due to the amount of light. Normally the pro- thallium of E., telmateia is not upright, but more or less decid- edly prostrate, as it is in the Ferns. (See Fig. 259, A.). 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 Campbell, Douglas Houghton, 1859-1953. New York, The Macmillan Company;
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