. The structure and development of mosses and ferns (Archegoniatae). e a thick dark-brown exospore and contain,chlorophyll and oil. The firstrdivisions take place before the-exospore is ruptured, and may §€ in thrfie planes, so that the V. MOSSES (MUSCI): SPHAGNALES—ANDRE^ALES 183 young protonema then has the form of a globular cell mass(Fig. 95, A). This stage recalls the corresponding one inmany of the thallose Hepaticae, e. g., Pellia, Rachila, and isentirely different from the direct formation of the filamentousprotonema of most Mosses. Some of the superficial cells ofthis primary tubercle
. The structure and development of mosses and ferns (Archegoniatae). e a thick dark-brown exospore and contain,chlorophyll and oil. The firstrdivisions take place before the-exospore is ruptured, and may §€ in thrfie planes, so that the V. MOSSES (MUSCI): SPHAGNALES—ANDRE^ALES 183 young protonema then has the form of a globular cell mass(Fig. 95, A). This stage recalls the corresponding one inmany of the thallose Hepaticae, e. g., Pellia, Rachila, and isentirely different from the direct formation of the filamentousprotonema of most Mosses. Some of the superficial cells ofthis primary tubercle grow out into slender filaments, eitherwith straight or oblique septa, and these later ramify exten-sively. Where there are crevices in the rock, some of thesebranches grow into them as colourless rhizoids. but, as in theBryales, there is no real morphological distinction betweenrhizoid and protonema. Most of the filamentous protonema!branches do not remain in this condition, but become trans-formed into cell plates or cylindrical cell masses, like the stem-.
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Keywords: ., bookauthorcampbelldouglashought, bookcentury1900, bookdecade1910
