Melanopsichium pennsylvanicum Hirschh.

Synonyms

Melanopsichium missouriense Whitehead & Thirum.
Melanopsichium pennsylvanicum var. besseyanum Zundel
Melanopsichium pennsylvanicum var. caulicola Zundel

Description

Sori usually in inflorescences but also in stems and leaves, as conspicuous purplish black irregularly lobed galls, elastic when young, viscid when mature and in humid conditions, firmly indurate when dried. Galls composed of hypertrophied host tissue containing numerous spherical to irregular chambers filled with spores embedded in a hyaline gelatinous matrix; in humid conditions the gelatinous substance swells considerably and pushes the spore mass out to the sorus surface.

Spores globose, ovoid to somewhat irregularly elongate, obpyriform, 7.5–15.0 × 6–11 µm, pale yellowish brown to light chestnut-brown; wall 0.7–1.0 µm thick, ±distinctly echinulate and with a ±distinct gelatinous sheath.

Spore germination resulting in 1 or 2 septate basidia with lateral and terminal ovoid to oblong hyaline basidiospores.

Hosts
   
Host family: Polygonaceae
   
Host species:

Persicaria lapathifolia (L.) Gray


Distribution

States & Territories: NSW, QLD

Comments

This species was reported as Melanopsichium austro-americanum (Speg.) Beck by McAlpine (1910: 163) who examined a specimen collected in 1879 on Polygonum sp. from Kelvin Grove, Brisbane, Queensland (BRIP 15380). However, M. austro-americanum has not been reliably reported in Australia, and many literature reports probably refer to M. pennsylvanicum (Vánky & Oberwinkler, 1994). The two species can be separated by the echinulate spores of M. pennsylvanicum in contrast to the smooth to minutely punctate-verruculose spores of M. austro-americanum.