. A textbook of botany for colleges and universities ... Botany. 114 MORPHOLOGY. ing in function the suppressed seta. It is formed by the elongation of the axis of the leafy branch beneath the sporophyte, and as it bears the capsule at its summit, it resembles an ordinary elongated seta (fig. 250). Of course the foot of the sporophyte is embedded in its tip. Conclusions.—The Sphagnales present a remarkable mixture of liverwort and moss characters. The simple thallus body of the gametopT]jte.iSaembies that of the anacrog3mous Jungermanniales; the^ecial leafy sFx^^^BrancKes su^est^the aLi'Ogyaou

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. A textbook of botany for colleges and universities ... Botany. 114 MORPHOLOGY. ing in function the suppressed seta. It is formed by the elongation of the axis of the leafy branch beneath the sporophyte, and as it bears the capsule at its summit, it resembles an ordinary elongated seta (fig. 250). Of course the foot of the sporophyte is embedded in its tip. Conclusions.—The Sphagnales present a remarkable mixture of liverwort and moss characters. The simple thallus body of the gametopT]jte.iSaembies that of the anacrog3mous Jungermanniales; the^ecial leafy sFx^^^BrancKes su^est^the aLi'Ogyaous Jungermanniales; while the spofoph)rte is organized as in the Antho- cerotaleT. On the other hand, the erect leafy branches of the gametophyte and the operculum of the sporophyte are both distinctly moss characters. In addition to these characters in common with liver- worts and true mosses. Sphagnum possesses Fig. 2^o.-Sphasnum: sporo- ^^j^^^. characters pecuhar to itself. phyte, showing the globular cap- * sule with operculum (lid) and It was remarked that the simplest con- dome-shaped mass of sporogenous ceivable liverwort would be produced by tissue (in tetrad stage), the very combining the gametophyte of Pellia^yiii short neckhke seta, the bulbous ° ° . „ . foot embedded in the apex of the the sporophyte of Rtccta. So m produc- leafy axis (gametophyte), which is ing Sphagnum, One might imagine a corn- extended beyond the leaves to ^ination of the gametophytes of the two form the stalkhke (seta-hke) ° 5, . , , pseudopodium. groups of Jungermanniales with the spo- rophyte of Anihoceros. The features of Sphagnum that distinguish it from true mosses in general are (i) the thallose gametophyte, (2) the axillary ajitheridia, (3) the dome-shaped sporogenous tissue derived from the amphithecium, and (4) the pseudopodium. Such a form is often called a transition form, but better a synthetic form, for it combines the characters of several groups. (2) Andreaeales General ch