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 Add this item to the list   802330 Original description
   
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Page number:1281 
Remarks (internal):Helvella vespertina resembles European H. lacunosa macroscopically but can form ascomata of gigantic proportions with stipes up to 20 cm tall and 10.5 cm across (see also Morse 1945). To our knowledge no European collections of H. lacunosa reach such dimensions. It is equally variable in colors, and complexity of the hymenium and also very similar in microscopic characters to H. lacunosa. When young it sometimes can be indistinguishable from H. dryophila (see description below), but the host tree and fruiting time will be the determining factors; it is also similar microscopically to H. dryophila. Older specimens of these species are more easily recognized and distinguished.
Thanks to sampling of ectomycorrhizal root tips in various locations, Pinus muricata and Pseudotsuga menziesii could be positively identified as conifer hosts for this species (Peay et al. 2010, Kranabetter et al. 2012). It also was found once on root tips of Arbutus menziesii in a predominantly conifer forest (Kennedy et al. 2012), although ascomata have not been collected in a pure A. menziesii stand.
Knowledge of host plant is an important feature (sometimes essential) in recognition of H. vespertina and H. dryophila, where H. vespertina associates with conifers and H. dryophila with oaks. This is also the case in distinguishing between two very similar European species, H. fusca Gillet and H. lacunosa based on the association of H. fusca with Populus (Landeros and Korf 2012). Therefore we recommend that a combination of host and macro-morphological characters be used to distinguish between H. dryophila and H. vespertina.
 
Description type:Original description 
Description:Helvella vespertina N.H. Nguyen & Vellinga, sp. nov.Figs. 1D-I, 4
MycoBank MB802330
Type collection: United States of America, California, Sonoma County, Salt Point State Park, 15 Jan 2012, T.W. Osmundson (UC 1999204), GenBank (KC122858).
Misapplied name: Helvella lacunosa sensu Morse, Mycologia 37:417. 1945 and sensu other American authors.
Ascoma 50-300 mm high. Pileus 25-55(-150) mm high, 25-50(-120) mm broad, with three almost smooth lobes and wavy when young developing brain-like convolutions with age, often with one lobe descending on stipe, light gray to dark gray, evenly colored to dark-spotty; apothecial surface pale when young to pale gray, sometimes with some anastamosing ribs, smooth, fused with stipe in several places. Stipe up to 250 mm high, up to 105 mm broad, cylindrical, with rounded to sharp, lengthwise, anastomosing ribs, grooved and lacunose, smooth, white, turning to gray with age, sometimes ochraceous along the lower portions of the stipe along the ribs (Fig. 1D-I).
Ascospores [61/4/4] l x w = 15.7-21.4 x 9.8-12.2(-13.7) µm, avl x avw = 17.1-17.6 x 10.9-11.4 µm, Q = 1.4-1.8, avQ = 1.55-1.6, smooth, with one guttule. Asci pleurorhynchous, not amyloid, with eight ascospores. Paraphyses cylindrical, 3-5 µm wide, with 4-9 µm wide apex, with brown intracellular pigment. Ectal excipulum trichodermal with terminal narrowly clavate to clavate, rarely cylindrical cells, 15-53 x 10-20 µm, with brown to dark gray parietal pigments (Fig. 4).
Habitat and distribution: In groups and clusters, terrestrial in forests and grassy verges, ectomycorrhizal with Pinus species (P. muricata, P. lambertiana, P. ponderosa), Pseudotsuga menziesii and possibly Abies concolor and Arbutus menziesii; widespread and common in the western parts of North America, at sea level in the coastal areas to around 1800 m in the Sierra Nevada and other mountain regions, known from Vancouver Island (British Columbia, Canada), California, Oregon and Idaho (USA.), covering a distance of approximately 1300 km and probably more widespread. Oct-Mar (rarely in Apr).
 
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