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Page number:402 
Remarks (internal):There seems to be no previous record of Alternaria spp. on species of Alismataceae (Farr et al 2008). Alternaria obpyriformis T.Y. Zhang (Zhang 1999) is morphologically close to the specimen of Alternaria from S. montevidensis, however it was recorded on Aloe vera var. chinensis (Haw.) Berger (Liliaceae) and the conidia are wider (12-22.5 µm). A trait that is applied to distinguish members of the Alternaria alternata species-group is the absence of conidial beaks or, in case these are present, their length never equaling the length of conidium body, but commonly reaching one-fourth to one-third of the total conidium length, according to Simmons (1967, 1995, 2007). Conidia of the specimen from S. montevidensis have a beak, occasionally as long as the conidium body (observed mainly on the original substrate, this trait was not observed in culture); this feature here was considered as not having sufficient significance to justify a distinction of the fungus on S. montevidensis as a new taxon. Cultural characteristics of the present specimen fit well with that of A. alternata (the sporulation pattern at lower magnification was similar to Group 4 classified by Simmons and Roberts [1993] as typical A. alternata). This is the first record of A. alternata on an alismataceous host worldwide.  
Description type:Non-original description 
Description:Alternaria alternata (Fr.) Keissler, Beih. Bot. Zentralbl. 29:434. 1912. Figs. 1c, 2a-d
Teleomorph. - Unknown.
Lesions on living leaves amphigenous, circular to elliptic, translucid, somewhat water soaked, sometimes with a yellowish margin, 5-10 mm diam, becoming confluent, always associated with insect damage. Internal hyphae 3-5 µm diam, branched, septate, hyaline to subhyaline, with thickened walls. External mycelium absent. Conidiophores amphigenous, single or in small groups of up to five, cylindrical, straight or sinuous, geniculate, 23-70 x 4-6 µm, 1-6-septate, brown, smooth. Conidiogenous cells polytretic, terminal or intercalary, integrated, cylindrical, with conspicuous scars, proliferating sympodially, 5-13 x 3-5 µm, pale brown to brown. Conidiogenous loci conspicuous, 1-3 per cell, 2-3 µm diam, thickened, darkened. Conidia single or catenulate, pyriform to ovoid-obclavate, up to 75 µm long, body 19-40 x 7-12 µm, beak 5-35 µm long, base rounded, with a thickened, darkened, 2-3 µm wide scar, golden brown to brown, 2-6 transversal septa, 2-4 longitudinal septa, smooth or slightly roughened.
Colonies on PDA fast growing (9 cm in 10 d) aerial mycelium well developed, cottony, sporulating, smoke-gray to gray-olivaceous, dark reverse with gray-olivaceous sectors; on MEA as on PDA, with whitish sterile sectors and dark gray sectors with sporulation; on OA fast growing, aerial mycelium poorly developed, sparse, immersed mycelium radiate, gray-olivaceous, sporulating, gray-olivaceous reverse with dark gray sectors.
Specimens examined. - All on leaves of Sagittaria montevidenis. Brazil: Rio Grande do Sul: Três Cachoeiras, Itapeva lake, 21 Apr 2005, D.J. Soares 182 (VIC 30509). Terra de Areia, roadside marsh on RS 486, 25 Nov 2005, D.J. Soares 464 (VIC 30526).
 
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