Claviceps hirtella Langdon

Description

Sclerotia formed in the fertile florets of spikelets, replacing the ovaries and always enclosed by, and shorter than, the lemma of the spikelet, subglobose often with a flattened apex, yellow-deep brown.

Conidia of three types

  • microconidia formed on narrow, flask-shaped terminal conidiogenous cells on the sphacelium and later immersed in honeydew, subglobose-globose, 3-5 µm in diameter, hyaline, aseptate.
  • macroconidia formed on narrow, flask-shaped terminal conidiogenous cells on the sphacelium and later immersed in honeydew, curved, elliptical-broadly falcate, 11-17 x 4-7 µm, hyaline, aseptate.
  • secondary conidia developed singly at the tips of sterigmata from germinated macroconidia above the honeydew surface, obovoid, 10-11 x 4-5 µm, hyaline, aseptate.

Stromata mostly one per sclerotium each consisting of a globose capitulum, 0.6-0.9 (0.5-1) mm in diameter, chestnut brown, papillate, persistant hyphae around the base of the stipe, borne by a thin cylindrical stipe 5-10 mm long, 0.3-0.5 mm in diameter, grey-pink, mostly smooth but bearing a few sparse hairs.

Perithecia immersed in capitulum, ovoid, 85-120 x 4-5 µm.

Asci cylindrical, 85-120 x 4-5 µm, base attenuated, with a hemispherical cap.

Ascospores filiform, 70-85 um long, hyaline.

Hosts
   
Host family: Poaceae
   
Host species: Brachiaria piligera
Brachiaria subquadripara
Brachiaria whiteana

Cenchrus ciliaris
Echinochloa crus-galli
Entolasia marginata
Entolasia stricta
Eriochloa meyeriana
Eriochloa procera
Eriochloa pseudoacrotricha
Megathyrsus maximus
Panicum bulbosum
Paspalidium distans
Pennisetum glaucum
Urochloa sp.


Distribution

NSW, QLD, WA

Comments

Langdon (1942) considered that the combination of the shape of the macroconidia, and the loose veil of hyphae on ascostromata were the distinquishing features for C. hirtella. Pažoutová et al. (2008) studied the Claviceps species with lunate–fusiform conidia using conidium morphology, partial sequences of rDNA and ß–tubulin, and alkaloid profiles, redescribing C. hirtella and C. fusiformis (on Cenchrus ciliaris and Pennisetum glaucum) and describing 3 new species from the Americas, (Claviceps eriochloae on Eriochloa sp., Claviceps texensis on Cenchrus ciliaris and Pennisetum glaucum) or Africa (Claviceps lovelessii on Urochloa sp. and Eragrostis spp.).  These authors considered that the Australian specimens of Cenchrus ciliaris that they examined belonged in C. hirtella, describing the macroconidia as being lunate-fusiform and 9-25 x 2-5.5 µm. The overseas occurences of multiple Claviceps species on grasses considered hosts of C. hirtella suggests that this species may not be the only Claviceps species with lunate-fusiform macroconidia in Australia.

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Claviceps hirtella on Pennisetum sp.
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Claviceps hirtella on Cenchrus ciliaris - BRIP 13544.
Scale bar = 1 cm.
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Claviceps hirtella on Eriochloa pseudoacrotricha - BRIP 8191.
Scale bar = 500 µm.
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Claviceps hirtella on Paspalidium sp. - BRIP 8195.
Scale bar = 500 µm.
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Claviceps hirtella on Paspalidium sp. - BRIP 8195.
Scale bar = 1 mm.
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Claviceps hirtella on Paspalidium sp. - BRIP 8195.
Scale bar = 500 µm.
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Claviceps hirtella on Cenchrus ciliaris - BRIP 13544.
Scale bar = 10 µm.
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Claviceps hirtella on Cenchrus ciliaris - BRIP 13544.
Scale bar = 10 µm.
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Claviceps hirtella on Cenchrus ciliaris - BRIP 13544.
Scale bar = 10 µm.
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Claviceps hirtella on Cenchrus ciliaris - BRIP 13544.
Scale bar = 10 µm.
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Claviceps hirtella on Cenchrus ciliaris - BRIP 16635.
Scale bar = 10 µm.