/& THE GASTEROMYCETES OF AUSTRALASIA. X. THE PHALLALES, PART I. By G. H. Cunningham, Mycologist, Plant Research Station, Palmerston North, N.Z. (Plates i-ii.) [Read 25th March, 1931.] This Order comprises a group of fungi characterized as a rule by the bizarre shape, bright colour and fetid odour of the spore-bearing receptacle. Two essential groups of tissues are common to all of them: (1) the peridium, a membrane enclosing the receptacle until maturity is reached; and (2) the receptacle, a pseudoparenchymatous structure upon which is borne the gleba or spore-mass. The fact that the hymenium is enclosed until maturity has led to the Order being placed in the Gasteromycetes. Morphology of the Mature Plant. Peridium. — In immature plants this structure appears as a globose or obovate structure of three layers (two in Claustula) : an outer, furfuraceous or smooth, usually white membrane (the exoperidium) ; a middle, thick and gelatinous layer (the mesoperidium) ; and an inner, thin and tough white membrane (the endo-peridium). Collectively these layers form in the unexpanded plant the outer layer of the "egg", and enclose the receptacle and gleba. At maturity the peridium ruptures from the apex downwards, splitting into several lobes, exposing the receptacle, and remains at the base of the latter, forming a stellate supporting cup or "volva". The receptacle is always free within the volva (save in Claustula, where it is at first attached by a fine basal strand), being held in position in expanded plants by lateral pressure of the receptacle against the cupulate base and edges of the lobes. The peridium is practically identical in all genera, consequently it is upon the diversity of structure exhibited by the receptacle that the numerous genera and species have been erected. Receptacle. — -In essentials this structure consists of a pseudoparenchymatous, usually coarsely chambered tissue, upon some modified portion of which is carried the gleba. It develops within the peridium, and as it approaches maturity, the receptacle is thrown into folds, the cells become strongly turgescent, and pressure is exerted upon the apex of the peridium, causing its rupture. The receptacle continues to expand, until finally it assumes a size considerably in excess of the peridium. Expansion is rapid, for in Aseroe rubra the plant is fully developed within one or two hours after rupture of the peridium. The gleba, borne on some portion of the receptacle, appears as a mucilaginous, olivaceous, fetid mass containing countless numbers of exceedingly minute, smooth, elliptical spores. A
BioStor
