On conidia of fungi, and gemmae of algae, bryophytes, and pteridophytes

Abstract

The methods of gemma production found in algae, bryophytes, and pteridophytes are considered in the light of those methods of conidium formation distinguished in fungi. Most gemmae are exogenous, but endogenous gemmae occur in a few Hepaticae. Solitary, blastic, sessile, or stalked gemmae, not accompanied by proliferation of the gemmifer, are found in the three groups of cryptogams. Gemmae produced from acropetally formed chains of initials are found in Hepaticae and Musci, and those from basipetally delimited chains of initials are found in Hepaticae only. In Hepaticae the gemmifers do not proliferate or extend, but in other groups solitary terminal gemmae can be formed on successive proliferations or extensions of the gemmifers. Thus, gemmae can arise on lateral, subterminal proliferations of the gemmifer in Musci and Filicales, and on percurrent proliferations of the gemmifer in algae and Musci. Also in Musci the gemmifer may bear a distal meristematic cell which cuts off a basipetal succession of gemmae. It is noted that Hepaticae, Musci, and Anthocerotae differ significantly in their respective methods of gemma production.The various kinds of proliferation of conidiogenous cells in fungi and of gemmifers in other cryptogams, and the feature of acropetal and basipetal delimitation of diaspore initials are discussed. A key to kinds of gemma production is presented.