Chaetomium globosum Kunze, Mycologische Hefte 1: 15, 1817.
= Chaetomium chartarum Ehrenberg, Sylv. Myc. Berol. 15: 27, 1818.
= Chaetomium fieberi Corda, Icones 1: 24, 1837. (fide Ames, 1963).
= Chaetomium lanosum Peck, Rep. New York State Mus. Natural History 28: 64, 1876. (fide Ames, 1963).
= Chaetomium fieberi var. chlorina Sacco Myc. Venet. X, 1876. (fide Ames, 1963).
= Chaetomium orientale Cooke, Grevillea 5: 103, 1877. (fide Ames, 1963).
= Chaetomium cymatotrichum Cooke, Grevillea 12: 21, 1883. (fide Ames, 1963).
= Chaetomium kunzeanum var. fimicolum Bommer & Rousseau, Bull. Soc. Roy. Bot. Belgique 23: 207, 1884. (fide Ames, 1963).
= Chaetomium oospora Beauverie, Ann. Univ. Lyon. Nouv. Ser. 1(3): 201, 1900. (fide Ames, 1963).
= Chaetomium elasticae Koorders, Verhand. d. K. Akad. v. Wternscappen te Amsterdam 134: 185, 1907. (fide Ames, 1963).
= Chaetomium kunzeanum var. chlorina Mich., Bull. Soc. Myc. France 25: 202, 1910. (fide Ames, 1963).
= Chaetomium subterraneum Swift & Povah, Mycologia 21: 210, 1929. (fide Ames, 1963).
= Chaetomium deustum Batista & Pontual, Bol. Sec. Agri Inc. & Com. Pernambuco 15: 72, 1948. (fide Ames, 1963).
= Chaetomium Kunzeanum Zopf. Nova Acta Leop. Carol. 42: 278, 1881.
= Chaetomium. mollipilium Ames, Mycologia 42: 644,·1950.
= Chaetomium coprophilum Narendra & Rao, Nova Hedwigia 27: 632, 1976.
= Chaetomium. rectum Serg., Not. Syst. Sect. Crypt. Inst. Bot. Acad. Sci. U.S.S.R. 14: 143, 1961.
= Chaetomidium. barbatum Traaen, Norw. in Nyt. Mag. Nat. Christiania 37,1914.
Ascomata ostiolate, subspherical to ellipsoidal, 170–250 × 160–250 µm. Peridium brown in transmitted light, 15–17 µm thick, forming a textura intricata in surface view. Rhizoids well-developed. Terminal hairs wavy to loosely coiled or straight, up to 700 µm long and 2.5–3.5 µm wide at the midpoint, moderately to coarsely blistered and septate. Lateral hairs straight to wavy, up to 200 µm long and 2.5–3.0 µm wide at the midpoint, moderately to coarsely blistered and septate. Asci clavate, 8-spored, 55–65 × 10–13 µm. Paraphyses present. Ascospores biseriate, brown in transmitted light, bilaterally flattened, broadly elliptic in front view and narrowly elliptic in side view, 8.8–10.5(11.0)x7.2–8.6 × 5.2–5.8 µm, with 1 apical germ pore. Ascogonial coil short stipitate and irregularly coiled. Mycelial hairs absent. Anamorph absent.
Czapek’s medium: Colony morphology variable. Mycelial growth rate 2.0–8.0 mm/day. Advancing margin even or very convoluted and appressed. Aerial mycelium abundant or absent. Immersed mycelium and reverse colour dark olive brown to hyaline. Ascomata absent or rarely scattered in some sectors.
Leonian’s medium: Mycelial growth rate variable, 1.5–6.0mm day. Advancing margin very convoluted and immersed or raised. Aerial mycelium absent. Reverse colour dark olive brown to strong yellow. Ascomata abundant and mature after 7–14 days. Ascomatal hairs variable in colour (see discussion of varieties).
Weitzman & Silva-Butner’s medium: Mycelial growth rate very fast, 5.5–9.0 mm/day. Advancing margin even and raised. Aerial mycelium cottony to funiculose and grayish yellow, obscured as ascomata develop. Reverse colour moderate olive to strong brown. Ascomata abundant and mature after 7 days. Ascomatal hairs variable in colour (see discussion of varieties).
Five varieties of C. globosum have been described and are distinguished by the following characters:
- var. flavo-viride Novak (1965): terminal hairs wavy, moderate olive to light olive green in reflected light.
- var. griseum Novak (1965): terminal hairs wavy, dark gray in reflected light.
- var. rectum Dreyfuss (1975): terminal hairs straight, moderate olive to light olive green in reflected light.
- var. arhizoides Dreyfuss (1975): terminal hairs wavy, dark gray in reflected light; rhizoids absent (material not seen).
- var. ochraceoides Dreyfuss (1975): terminal hairs wavy, bright olive green in reflected light (material not seen).
According to the Botanic Code one of these varieties should be designated var. globosum. However, it has not been possible to obtain type material of Chaetomiurn globosum for this purpose, and I hesitate to neotypify the species until material from the type locality, Leipzig (D.D.R.), becomes available.
Specimens examined: C. globosum var. flavo-viride. CANADA: TRTC 48776, isolated from human hand, Ontario. TRTC 48779, from caribou dung, N.W.T. (near Cape Bathurst). TRTC 48776, isolated from wasp nest, Ontario.*TRTC 48780, isolated from greenhouse soil, Ontario. HLX 840, isolated from pasture soil, Nova Scotia. U.S.A.: *TRTC 48737, isolated from soil under Liguidambar sp., Maryland. *TRTC 48747, from mouse dung, Illinois. COSTA RICA: TRTC 48758, isolated from forest soil, Monteverde. BRAZIL: * TRTC 48740, isolated from forest soil, Ceara. TANZANIA: TRTC 66.1719c, from herbivore dung, Kijuca Ngwelo Hill. FRANCE: TRTC 48771, from sheep dung, Provence. INDIA: TRTC 48766, from camel dung, Maharashtra, (from type of Chaetomium coprophilum). THAILAND: TRTC 48748, isolated from orchid leaf, near Pak Thong Chai.*TRTC 48750, isolated from rice straw compost, Ben Yang. SOLOMON ISLANDS: QM 154c, isolated from musette bag, New Georgia. *QM 153b, isolated from mosquito netting, New Georgia.
C. globosum var. griseum. CANADA: TRTC 48767, isolated from wolf dung, N.W.T. (near Tuktoyaktuk). TRTC 48753, isolated from carnivore dung, Ontario. TRTC 48752, isolated from heavy metal contaminated soil, Ontario. U.S.A.: isolated from sugar cane, Hawaii. QM 459, isolated from cotton fabric, Washington D.C. COSTA RICA: TRTC 48749, isolated from forest soil, Monteverde.
C. globosum var. rectum. U.S.S.R.: DAOM 93116, on old herbarium packet (culture from type of Chaetomium rectum). CANADA: TRTC 48778, isolated from deer dung, Ontario. TRTC 35600, isolated from pea stems, Ontario. SOLOMAN ISLANDS: QM 1007, isolated from raincoat, New Guinea, (culture from type of Chaetomium mollipilium). QM 1008, isolated from tent, New Guinea. KENYA: TRTC 66.20, isolated from zebra dung, Aberdare Mts.
Notes: Chaetomium globosum is obviously highly variable and as a result may be confused with several closely related species. Chaetomium ochraceum Tschudy can be distinguished by its smaller ascospores and distinct colony morphology. Chaetomium coarctatum Serg. produces a similar colony to that of C. globosum but is differentiated by its very broad ascospores (8.7–10.1 µm wide in front view). Chaetomium kunzeanum Zopf. and C. subglobosum Serg. produce somewhat larger ascomata and ascospores than C. globosum. In addition, both C. subglobosum and C. kunzeanum form a phialidic anamorph. Chaetomium olivaceum Cooke & Ellis is morphologically similar to C. kunzeanum but does not produce an anamorph (Muller & Sedlar, 1978). For a more detailed discussion of C. olivaceum refer to the species description of C. kunzeanum. Extremely atypical forms of Chaetomium cochliodes Palliser may resemble C. globosum var. flavo-viride, however, they can usually be distinguished by colony morphology and ascospore shape. The ascospores of C. cochliodes have more well developed apiculi at the ends of the spores, and on Leonian’s medium, C. cochliodes usually produce non-ostiolate ascomata with poorly differentiated hairs while C. globosum var. flavo-viride forms ostiolate ascomata with well differentiated hairs.
The immature ascospores of C. globosum have been described as slightly reddish (Domsch et al., 1980; Dreyfuss, 1975),however, I have only observed this colour in spores mounted in lactic acid. In water, the young ascospores are hyaline. The colour change is probably a reaction to the lactic acid mounting medium and not a naturallu occurring condition. I have seen this same reaction in immature ascospores of C. cochliodes.
In an examination of Chaetomium species for cytotoxic metabolites, Udagawa et.al. (1979) reported that culture of C. mollipilium (QM 1007), C. rectum Serg. (CBS 164.62 = DAOM 93116) and C. subaffine (TRTC 35600) produce highly carcinogenic compounds (chaetoglobosins). All 3 of the above cultures have been examined either by Dr. M Dreyfuss or myself and are considered to represent Chaetomium globosum var. rectum Dreyfuss.
It should be noted that isolate QM 459 (= CBS 148.51 = IFO 6347 = USDA 1042.4= ATCC 6205 = NRRL 1870-NRC V-159 = CMI 45,550) represents C. globosum var. griseum. This culture has been used extensively in testing mould proofing.
A great deal has been published of the physiology, biochemistry, and habitat preferences of C. globosum. For an account of such studies the reader is referred to Domsch et al. (1980). Aspects of the ascomatal development of C. globosum are reported by Chadefaud & Avellanas (1967), Whiteside (1957) and Froeyen (1980).
|Collection number||Ascospore size (µm) (mean) (front view)6||Growth rate on Weitzman & Silva-Hutner medium (mm/day) (27 °C)|
|TRTC 48771||9.6 × 7.7||7.5 – 8.0|
|TRTC 48776||9.3 × 7.6||7.5 – 8.0|
|QM 154c||9.5 × 7.9||8.5 – 9.0|
|TRTC 48779||9.7 × 7.8||7.5 – 8.0|
|TRTC 48751||9.3 × 7.6||7.5 – 8.0|
|TRTC 48748||10.0 × 8.1||5.5 – 6.0|
|TRTC 48563||9.8 × 7.8||7.5 – 8.0|
|QM 153b||9.6 × 7.8||7.0 – 7.5|
|TRTC 48758||9.8 × 7.9||7.5 – 8.0|
|TRTC 66.1719c||9.7 × 7.7||7.5 – 8.0|
|TRTC 48766||9.7 × 8.3||7.5 – 8.0|
|HLX 840||9.7 × 7.9||8.0 – 8.5|
|TRTC 48767||9.6 × 7.8||8.5 – 9.0|
|QM 459||9.6 × 7.8||7.0 – 7.5|
|TRTC 48781||9.5 × 7.4||7.0 – 7.5|
|TRTC 48753||9.3 × 7.7||7.5 – 8.0|
|TRTC 48752||9.3 × 7.7||6.5 – 7.0|
|QM 2664||9.5 × 7.6||7.5 – 8.0|
|TRTC 48749||10.0 × 7.9||7.5 – 8.0|
|DAOM 93116||9.7 × 7.8||7.5 – 8.0|
|TRTC 48778||10.0 × 8.3||8.0 – 8.5|
|QM 1007||9.4 × 7.9||8.0 – 8.5|
|QM 1008||9.6 × 7.7||8.0 – 8.5|
|TRTC 35600||9.6 × 7.5||7.5 – 8.0|
|TRTC 66.20||9.6 × 7.6||8.0 – 8.5|
Chaetomium globosum Kunze, Mycologische Hefte 1: 15, 1817.
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