Miltidea Stirt.
Type : Lecidea rubricatula Stirt. [=Miltidea ceroplasta (C.Bab.) D.J.Galloway & Hafellner]
Description : Thallus crustose, pale greyish white, spreading in irregular patches, without a prothallus, corticolous. Photobiont green, trebouxioid. Ascomata apothecia, scattered, mainly solitary, sessile, rounded, biatorine, orange-red to red-brown. Epithecium granular, yellow-brown, opaque, K+ purple. Hymenium to 80 μm tall, colourless, inspersed with oil droplets. Hypothecium opaque, yellow-brown. Hamathecium of paraphyses, branched and anastomosing. Ascus cylindrical–clavate, with an amyloid tholus, Miltidea -type (Malcolm & Galloway 1997: 187), 8-spored. Ascospores simple, colourless, ellipsoidal, halonate. Conidiomata pycnidia, immersed, ostiole orange-red. Conidia colourless, bacillar to falcate.
Stirton (1898: 384) in commenting on his newly proposed generic name of Miltidea referred to it the following taxa: Lecidea (Miltidea) cinnabarina Sommerf., Lecidea (Miltidea) russula Ach. and Lecidea (Miltidea) laeta Stirt., all of which are currently referred to Pyrrhospora (Hafellner 1993b). The description of Miltidea given by Stirton is in the form of comments on his earlier taxon Lecidea rubricatula Stirt. (Stirton 1875b: 468) viz.: "...Under L. rubricatula are several forms. One of these is L. cinnabarodes [sic], Nyl. (Lich. N.Z., 1889). Nylander describes the thallus of his lichen as being "albidus opacus tenuissimus." With one exception this description does not tally with any condition of the thallus I have seen. The thallus as described by me in Journ. Linn. Soc., 1876 [sic] agrees much more nearly with the numerous specimens from New Zealand in my herbarium – viz, "griseo-pallescens crassus diffracto-areolatus". In this paper I have given the dimensions of the spores as rather too great. They may be described as 0.014–0.022 mm. × 0.007–0.011 mm. The dimension, 0.016 mm, there given is a misprint for 0.013. It is exceedingly difficult to get a specimen in this species having fully-developed spores".
Stirton's species Miltidea consanguinea from decorticated wood in Australia from a collection of Hugh Paton (Stirton 1898: 385) is referred to Biatorella by Zahlbruckner (1927: 35) and by Filson (1986, 1996). Both Rogers (1982b: 505) and Filson (1986: 148) claim not to have located type material of this species in Stirton's herbarium in GLAM, but material of it might possibly be found in the unincorporated Stirton lichens at BM.
Miltidea, a monospecific genus, is included in the monogeneric family Miltideaceae (Hafellner 1984; Eriksson et al. 2004; Kantvilas 2004b; Pennycook & Galloway 2004) based on ascus and spore type. The ascal tholus turns blue in iodine and does not show any further structures. The ascus type suggests some affinities with the Acarosporineae and it was proposed tentatively to place the family Miltideaceae in this suborder (Lumbsch 1997b: 65), but currently it is included in the Lecanorineae (Eriksson 2005). The single known species is widely present in New Zealand.
