Claviceps rhynchelytri G.W. Herd & A.R. Loveless

Description

Sclerotia formed in the fertile florets of spikelets and replacing the ovaries and projected slightly from the spikelet elements, ellipsoidal, with a spherical knob at the tip, up to 5 mm long, 1 mm wide and 0.5 mm thick, dark brown, dispersed by disarticulation of entire spikelet.

Conidia
of two types

  • macroconidia formed on narrow, flask-shaped terminal conidiogenous cells on the sphacelium and later immersed in honewydew, reniform, 6-11 x 2-5 µm , hyaline, aseptate.
  • secondary conidia developed singly at the tips of sterigmata from germinated macroconidia above the honeydew surface, broadly ovate, 7-9 x 3-4 µm, hyaline, aseptate.

Ascostromata 1 or sometimes 2 per sclerotium, each consisting of a subglobose or hemispherical capitulum up to 1.1 mm in diameter, bright yellow, papillate on sides and top, borne on a slender stipe, up to 12 mm long, 0.3-0.4 mm wide, straw-coloured, smooth, narrowing towards the point of attachment to capitulum, sometimes extending inwards into the capitulum for as much as one third of its height.

Perithecia ovoid, with a short neck, 185-205 µm long (including the neck) x 100-125 µm wide, the neck opening at the apex of a papilla.

Asci cylindrical, variable in length, mostly 140-150 µm long, apex with a distinct hyaline cap, base attenuated.

Hosts
   
Host family: Poaceae
   
Host species: Melinis minutiflora
Melinis repens

Distribution

NSW, QLD

Comments

This species has been recorded only on Melinus, which are common roadside grasses in Queensland and northern New South Wales.

Highslide JS
Claviceps rhynchelytri on Melinis repens - BRIP 20084.
Scale bar = 1 cm.
Highslide JS
Claviceps rhynchelytri on Melinis repens - BRIP 13088.
Scale bar = 10 µm.
Highslide JS
Claviceps rhynchelytri on Melinis repens - BRIP 13088.
Scale bar = 10 µm.
Highslide JS
Claviceps rhynchelytri on Melinis repens - BRIP 13088.
Scale bar = 10 µm.
Highslide JS
Claviceps rhynchelytri on Melinis repens - BRIP 13088.
Scale bar = 10 µm.