ISOLATES EXAMINED: IMI 156096 &CBS 101.69 & FRR 722, type isolate, from a mine tip with a very high surface temperature, Staffordshire, G.B., 1967, H. C. Evans; CBS 105.69 & FRR 729, from spruce chips, Skogshogskolan, Stockholm, Sweden, 1964; T. Nilsson; IMI 154253 & FRR 1170, from bagasse, Trinidad, 1971, J. Lacey.

CYA, 25^oC, 7 days - Colonies 15-25 mm diameter, plane, typically velutinous to lightly floccose, one known isolate strongly funiculose; margins entire or fimbriate; mycelium white; conidiogenesis very light to moderate, Greyish Yellow near Sand (M. 4133); exudate and soluble pigment absent; reverse dull yellow or brown. MEA, 25^oC, 7 days - Colonies 15-22 mm diameter, plane, lightly floccose to somewhat funiculose; margins entire; mycelium white; conidiogenesis moderate, colored as on CYA; exudate and soluble pigment absent; reverse pale to dark brown. G25N, 25^oC, 7 days - Colonies 3-6 mm diameter, occasionally less, characters as on CYA. 5°C, CYA, 7 days-No germination. 37^oC, CYA, 7 days-Colonies 30-45 mm diameter, sparse to moderately dense, radially sulcate, velutinous to funiculose; mycelium white; conidiogenesis light, colored as on CYA; exudate and soluble pigment absent; reverse pale to deep yellow brown. Conidiophores borne from surface or aerial hyphae, stipes ranging from 60-400 µm x 3.0-4.0 µm, with verrucose walls, bearing penicilli of variable complexity, sometimes monoverticillate (especially on MEA), commonly biverticillate but with terverticillate or quaterverticillate struc tures also usually produced; rami 15-20 µm x 3.0-4.0 µm, walls verrucose; rarnuli 10-15 µm x 3.0-4.0 µm, walls verrucose; metulae in verticils of two or three, measuring 10-20 µm x 2.5-4.0 µm, often with enlarged apices, walls verrucose; phialides 8-10 per metula, commonly 9-11 µm x 2.0-2.8 µm, with verruculose walls, narrowing gradually to long collula; conidia cylindroidal, 3.5-4.0 µm x 2.0-2.5 µm, walls smooth to verruculose, borne in disordered chains.

TYPIFICATION: Herb. CBS 101.69 was designated as holotype by Stolk et al. (1969). Herb. IMI 156096 is isotype material.
DISTINGUISHING CHARACTERS: As noted by Stolk e t al. (1969), Geosmithia argillacea is apparently closely related to G. cylindrospora. Geosmithia argillacea grows more rapidly on CYA at 25^°C and especially at 37^°C, whereas conidia of G. cylindrospora en masse are colored much darker brown. Unlike those of G. cylindrospora, phialides of G. argillacea taper gradually towards the apices.
Stolk et al. (1969) reported that Geosmithia argillaea is thermotolerant, with an optimal growth temperature near 35^oC and a maximum near 50°C. It has been isolated from hot environments such as a mine tip and wood chip piles.

ISOLATES EXAMINED: IMI 40212 & NRRL 2024 & FRR 2024 (=CBS 233.38, ATCC 10487), neotype of Geosmithia putterillii, from decaying timber, New Zealand, J. C. Neill; IMI 40214 & NRRL 2037 & FRR 2037 (= CBS 260.33, ATCC 10478, IFO 5758), type of Penicillium pallidum, from yarn, G.B., G. Smith; IMI 51240b, from Persea gratissima, Seychelles, 1952, G. S. Brown; IMI 133283 & FRR 1705, from soil, Giza, Egypt, M. K. Moawod; IMI 155478a, from branch of Malus pumilus, Cyprus, 1971, J. P. Zyngas and IMI 191599, from a similar source, 1975; IMI 158645 & FRR 1706, from seed of Hordeum vulgaris, Boxworth, G.B., 1971, J. Lacey; IMI 190744, from Cucumis melo, Peru, 1974, A. Wallbridge; FRR 839 (= CBS 342.52) from an unrecorded source, Netherlands, 1952, C. A. de Vrie s; FRR 1119, from air in laboratory, Melbourne, Victoria, Australia, 1970, H. J. Sivart.

CYA, 25°C, 7 days - Colonies typically 25-35 mm diameter, plane or lightly sulcate, velutinous, lightly floccose or somewhat funiculose; margins subsurface; mycelium white to buff; conidiogenesis moderate to heavy, colored Yellowish White (M.4A2); exudate and soluble pigment absent; reverse dull yellow or olive brown. MEA, 25^oC, 7 days - Colonies 20-30 mm diameter, plane, velutinous, floccose or, more characteristically, strongly funiculose; other characteristics similar to colonies on CYA. G25N, 25^oC, 7 days - Colonies typically 15-18 mm diameter, occasionally larger or smaller, with all characteristics similar to colonies on CYA. 5^oC, CYA, 7 days-Response variable, no germination to formation of microcolonies. 37°C, CYA, 7 days-Typically no growth; some isolates producing colonies up to 8 mm diameter, similar in appearance to those at 25^oC. Conidiophores borne from subsurface, aerial or funicular hyphae depending on growth character, stipes commonly 20-100 µm x 3.0-4.0 µm, with verrucose walls, characteristically bearing terminal penicilli of variable complexity, commonly with two or three branch points, but penicilli with four or five branch points between stipe and conidium also occurring, frequently so in some isolates; rami 15-20 (-30) µm x 3.0-4.0 µm, with verrucose walls; metulae 10-15 µm x 3.0-3.5 µm, with verrucose walls; phialides cylindroidal or tapering slightly towards the apices, 8-10 (-12) µm x 2.5-3.0 µm, with walls verruculose to verrucose; conidia cylindroidal, 4.0-5.0 µm x 2.0-2.5 µm, smooth walled, borne in long disordered chains.

TYPIFICATION: Thom's type of Penicillium puttcrillii was soon lost (Thom 1930: 368). Herb. IMI 40212 is designated as neotype. This is derived from NRRL 2024, considered by Raper and Thom (1949: 462) to represent the species.
DISTINGUISHING CHARACTERS: Conidia en masse are white or off-white; growth at 37°C is slow or absent; penicilli are of variable complexity, usually with two or three, but sometimes four or five branch points.
TAXONOMY: Raper and Thom (1949) regarded Penicillium putterillii and P. pallidum as separate species based on differences in conidial color and arrangement of conidial chains. Several new isolates examined here have exhibited properties intermediate between the two species, so P. pallidum has been placed in synonymy with Geosmithia putterillii.