LSU-RPB2-ITS consensus Bayesian phylogram of genus <i>Picoa</i> reconstructed in MrBayes 3.1.

<p>Bold nodes are significantly supported by both inference methods employed (>70% BP and >95% PP). Nodes annotated were significantly supported by only one of these methods. Values represent Bayesian posterior probabilities, and RAxML bootstrap proportions, respectively.</p

Collection of <i>Picoa</i> species studied in the present work.

<p>Collection of <i>Picoa</i> species studied in the present work.</p

Type studies in African <i>Picoa</i> lineage.

<p><b>a-e</b>. <i>Phaeangium lefebvrei</i> holotype FH 301557; <b>f-h</b>. <i>Terfezia schweinfurthii</i> syntype S F8693; <b>i-m</b>. <i>Picoa lefebvrei</i> M 157945. Bars: 5 μm.</p

ITS consensus Bayesian phylogram of genus <i>Picoa</i> and its sister taxon <i>Geopora</i> reconstructed in MrBayes 3.1.

<p>Bold nodes are significantly supported by both inference methods employed (>70% BP and >95% PP). Nodes annotated were significantly supported by only one of these methods. Values represent Bayesian posterior probabilities, and RAxML bootstrap proportions, respectively.</p

SEM and LM images of some of the samples studied.

<p><b>a-b</b>. Autoptic specimen of <i>Picoa juniperi</i> from Vittadini’s herbarium WU10-145 ex PAD; <b>c</b>. BMBH1; <b>d</b>. BMBT26; <b>e</b>. AH 19584; <b>f</b>. M-0157945; <b>g</b>. AH 39246; <b>h</b>. AH 39286; <b>i</b>. AH 38931; <b>j</b>. AH 39206; <b>k</b>. BMBH9; <b>l</b>. BMBH5; <b>m</b>. BMBO19. Bars: <b>a</b> = 10 μm; <b>b</b> = 5 μm; <b>c-d</b> = 5 μm; <b>e-f</b> = 5 μm; <b>g</b> = 10 μm; <b>h-j</b> = 5 μm; <b>k-l-m</b> = 5 μm.</p

Geographic origin of the collections belonging to the two major lineages observed.

<p>Lineage II in green; lineage VI in blue.</p

Macroscopical images of some of the samples studied.

<p><b>a</b>. AH 39247; <b>b</b>. AH 39268; <b>c</b>. VK 2043; <b>d</b>. VK 2106; <b>e</b>. AH 38906; <b>f</b>. AH 39139; <b>g</b>. AH 38893; <b>h</b>. AH 38956; <b>i</b>. VK 2148; <b>j</b>. habitat of <i>Picoa</i> in Castilblanco de Henares (Guadalajara, Spain); <b>k</b>. habitat of <i>Picoa</i> under <i>Helianthemum lippii</i> var. <i>sissiliflorum</i>; <b>l</b>. BMBC15; <b>m</b>.BMBH4.</p

Contrasted Genetic Diversity, Relevance of Climate and Host Plants, and Comments on the Taxonomic Problems of the Genus <i>Picoa</i> (Pyronemataceae, Pezizales)

<div><p>The species concept within the genus <i>Picoa</i> Vittad. is here revisited in light of new molecular and ecological data obtained from samples collected throughout the Mediterranean basin. Two highly diverse widespread clades and four additional minor lineages were significantly supported by three genes dataset (ITS, 28s LSU and RPB2) inferences for 70 specimens. The two widespread clades occur in very different geographical and ecological areas associated with exclusive host plants in the genus <i>Helianthemum</i>. SEM study of spore surface morphology in these lineages revealed the existence of smooth ascospores in the majority of these clades. However the most frequent lineage in Europe and coastal North Africa displayed either smooth or verrucose spores. Hence this morphological criterion cannot be reliably used to discriminate between the different clades. In addition, SEM observations made on ascospores from several original collections of <i>P</i>. <i>juniperi</i> and <i>P</i>. <i>lefebvrei</i> supported the hypothesis that ornamentation depends on the degree of maturity in some of these lineages. Geographical and ecological, rather than morphological data are here suggested as the most useful characters to separate the different lineages in <i>Picoa</i>. Further studies focusing on these features are needed before the names <i>P</i>. <i>juniperi</i> and <i>P</i>. <i>lefebvrei</i> can be unambiguously linked with the genetic lineages observed.</p></div