HEMITRICHIA SERPULA VAR . PIAUIENSIS ( TRICHIACEAE , MYXOMYCETES )-A NEW VARIETY FROM BRAZIL

(Hemitrichia serpula var. piauiensis (Trichiaceae, Myxomycetes) A new variety from Brazil). A new variety of Hemitrichia serpula (Scop.) Rost. from Brazil, H. serpula var. piauiensis Cavalcanti & Mobin, is described and illustrated. The new taxon has a somewhat less spinulose capillitium, with short and scattered spines; spores are finely reticulate , with well-defined meshes. The type is deposited in the Herbarium UFP, Myxomycete Collection, Federal University of Pernambuco (Recife, Pernambuco State, Brazil). A key to the three varieties of the species is presented as well.

Plasmodiocarps of H. serpula with reticulated spores and capillitium bearing long spines were collected in Piauí State, Northeastern Brazil.Among several specimens which fruited on palm trees, recently collected in this State, seven proved to be a new variety of this species.It is described and illustrated in this paper.
The material was observed through the light microscope (LM) under oil immersion objective (Teixeira 1971), and with the scanning electron microscope (SEM).Fructifications were prepared for scanning electron microscopy as follows: capillitium and spores were placed on double adhesive cellophane tape mounted on a specimen stub, sputter-coated with gold (Fine coat sputter JFC-1100), and examined in a JEOL-JSM-T200 Stereoscan (Nelson et al. 1982).
The nomenclature followed in this paper is that of Martin et al. (1983) and Martin & Alexopoulos (1969).The yellow plasmodiocarp of Hemitrichia serpula var.piauiensis is macroscopically similar to those of var.serpula or var.tubiglabra, but the specimens described in this paper differ from those varieties in the ornamentation of spores and capillitium.As observed in the light microscope, the capillitia of both var.serpula and var.piauiensis show spiral thickenings and spines connected by small ridges parallel with the length of the threads.However, the threads of var.serpula are more densely spinulose, with long and slender spines, while those of var.piauiensis have scattered, shorter spines (Fig. 1-4).The capillitial threads of var.tubiglabra, by contrast, are distintive in their thickness (8.0-9.0µmdiam.) and smooth spirals (Fig. 5-6).On both types of threads, the spiral thickenings and spines are connected by small ridges parallel with the length of the threads.

Hemitric
The spores of var.piauiensis differ from  those var.serpula by the fine reticulations in the wall, which are barely visible through the LM at low magnification; under the oil immersion objective the spore wall ornamentation is more clearly seen as verrucose or warty-reticulate (Fig. 2).
The spores and capillitia of the two varieties are still better distinguished by the SEM (Fig. 7-9).Figure 7 shows that the spore wall of var.piauiensis, which looks verrucose or wartyreticulate under the LM, is in reality bandedreticulate.