A new approach to species delimitation in Septoria

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Date: June 2013
From: Studies in Mycology(Vol. 75)
Publisher: Centraalbureau voor Schimmelcultures
Document Type: Report
Length: 30,827 words
Lexile Measure: 1320L

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Septoria galeopsidis Westend., Bull. Acad. r. Belg., Cl. Sci., Ser. 2, 2: 577. 1857. Fig. 20.

= Ascochyta galeopsidis Lasch in Rabenh., Herb. Myc. I, 1058. 1846 [nom. nud.].

= Septoria cotylea Pat. & Har., Bull. Soc. Mycol. France 21: 85. 1905.

Description in planta: Symptoms leaf spots irregular or angular, becoming dark brown, in yellow parts of the leaf lamina. Conidiomata pycnidial, hypophyllous, often numerous in each leaf spot, globose to subglobose, dark brown, almost completely immersed, 75-100(-130) [micro]m diam; ostiolum central, initially circular, 15-25 [micro]m wide, surrounding cells somewhat darker; conidiomatal wall 10-22 [micro]m thick, composed of textura angularis without distinctly differentiated layers, the cells 3-8 [micro]m diam, the outer cells with brown, somewhat thickened walls, the inner cells with hyaline and thinner walls. Conidiogenous cells discrete, sometimes integrated into 1-2-septate conidiophores, hyaline, narrowly or broadly ampulliform with a relatively narrow neck, holoblastic, proliferating percurrently with indistinct annellations, and also sympodially, 6-12(-15) x 3.5-5(-6) [micro]m. Conidia filiform, straight or slightly curved, sometimes flexuous, with a rounded or somewhat pointed apex, attenuated towards the narrowly truncate base, (0-)3(-5)-septate, not constricted around the septa, hyaline, contents with several minute oil-droplets and granular material in each cell in the living state, with inconspicuous oil-droplets and granular contents in the rehydrated state, 20.5-44 x 1.5-2.5 [micro]m (living; rehydrated, 1-2 [micro]m wide). Sexual morph unknown.

Description in vitro: Colonies on OA 7-13 mm diam in 2 wk (35-43 mm in 6 wk), with an even, glabrous, colourless margin; colonies almost plane, immersed mycelium homogeneously olivaceousblack to greenish black (also near the margin); aerial mycelium scanty, woolly-floccose, white or greyish; superficial pycnidial conidiomata scanty, scattered over the central aerea, releasing milky white droplets of conidial slime; reverse dark slate blue to black. Colonies on CMA 7-13 mm diam in 2 wk (33-37 mm in 6 wk), as on OA, but concentration of conidiomatal development in elevated pustules on the elsewhere flat colony. Colonies on MEA 6-11 mm diam in 2 wk (33-39(-46) mm in 6 wk), the margin even, later undulating, buff, narrow and glabrous; colonies hemispherical, often irregularly pustulate or with columnar outgrowths up to 5 mm high, immersed mycelium olivaceous-black to black, mostly covered by a dense mat of finely velted, greyish aerial mycelium; faster growing, glabrous sectors with buff immersed mycelium may appear after several weeks; conidiomata starting to develop on the (dark) colony surface, tardily sporulating with whitish to flesh droplets of conidial slime; reverse brown-vinaceous or olivaceousblack. Colonies on CHA 5-10(-15) mm diam in 2 wk (20-29 mm in 6 wk), with an even, glabrous to nearly so, buff margin; colonies irregularly pustulate, immersed mycelium olivaceous-black, mostly covered by a dense but appressed mat of woolly-floccose, grey aerial mycelium, in some slightly faster growing sectors pure white; scattered but scarce superficial conidiomata releasing pale flesh droplets of conidial slime; reverse blood colour to black.

Conidiomata pycnidial and similar as in planta, 100-150 [micro]m diam, or merged into larger complexes especially on the agar surface, dark brown, up to 200 [micro]m diam;...

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Gale Document Number: GALE|A473631579