Our collections and analyses supplement and broaden the knowledge and distribution of morels in South America. Based on four-gene and ITS phylogenies, the specimens collected in this study were assigned to Elata clade lineages that were first identified as occurring in South America by Pildain et al. (2014) and Machuca et al. (2021) (Figure 1 and 2). Two of these lineages, M. andinensis/Mel-37 and M. aysenina are unique to South America (Pildain et al. 2014; Machuca et al. 2021).
Morchella tridentina represents one of the most widely collected morel species in southern South America as reported by Pildain et al. (2014) for Argentina, and Machuca et al. (2021) and this study for Chile (Figures 1 & 2). It was also found frequently in the studies of Taşkın et al. (2012) for Turkey. Loizides et al. (2017) highlight that M. tridentina is geographically wide ranging and is found mostly in undisturbed areas, and unlike M. rufobrunnea, which is ruderal, M. tridentina has been collected with native vegetation and thus may not be introduced as Pildain et al. (2014) suggested.
The majority of the mitosporic colonies collected in our study belong to the M. eximia lineage (Figure 2). The M. eximia clade also included Argentine collections from Pildain et al. (2014) reported as M. septimelata. Machuca et al. (2021) did not report M. eximia from among their Morchella collections from Nothofagaceae forests in Chile.
Our collections also represent two lineages unique to South America, M. andinensis/Mel-37 and M. aysenina. Analysis of ITS rDNA sequence data (Figure 2) expanded the M. aysenina clade of Machuca et al. (2021) to include a new Morchella ascomatal collection, M1, and mitosporic mat (MES-2752) (Table 1 and 2). Five of our mitosporic collections are represented in the M. andinensis/Mel-37 lineage along with six ascomatal collections thus expanding the geographic distribution of this species as well. An additional mitosporic mat collection (MES-3944) was recently made in Chile during a 2022 collecting trip. An incomplete sequence of this collection was not included in our analysis but it appears to be part of the M. andinensis clade based on initial ML analysis.
The incorporation of field collections of the Costantinella mitosporic mats from southern South America builds on the work of Healy et al. (2013) and Carris et al. (2015). Carris et al. (2015) specifically correlated mitospore colonies and ascomata of Morchella species from collections in the Pacific Northwestern USA. The mitospore mats collected in this study were morphologically similar to those reported by Carris et al. (2015); these all belong to the Elata clade of Morchella (Richard et al. 2015). The distinctive verrucose setae observed among the conidiophores by Carris et al. (2015) were also found in our specimens. It remains to be seen if mitospore colonies in the Esculenta clade also produce setae. The mature length of sporogenous tips of the four Morchella species studied here are relatively short as compared to the Gyromitra and Disciotis anamorphs reported in the Carris et al. (2015) study, and most are recurved, but there were examples in M. aysenina and M. andinensis where some of the conidiogenous cells remained straight at maturity.
Judging from our specimens collected from nature and those described from culture by Carris et al. (2015) there are few characters that can be used to distinguish among the species based on the mitosporic state. In culture the colonies are fawn color, and the hyphae are pale to medium brown. This corresponds to the appearance of the field collected specimens. Setae attain a length of up to 70 µm with a great deal of variation. The setae are pigmented and verrucose below and tend to be smooth and hyaline near the apex. Similar variations are seen in conidiophore length and pigmentation. There are some structural differences in the arrangement and number of verticels (from 3 to 6 per locus), the amount of secondary branching, and the degree of crowding along the length of the conidiophore. These characters may all be malleable and affected by the conditions under which they develop. We did not attempt to culture our collections. The uniformity of morphology among the species studied so far suggest that identification will require DNA sequence acquisition.
Several Morchella species have been previously reported in South America. Patouilliard & Lagerheim (1891) list M. conica (though unverified, this is part of the Elata clade) from Ecuador and state that their report is the first report of the species from South America. Gamundí (1975) described a single Morchella collection as M. elata from Port Harberton in Argentine Tierra del Fuego. It is dark brown, almost black, similar in color to those in Europe. She noted the variations in ascospore size and shape of the pileus, stating that her collection agrees with the description given by Rifai (1968) for material from Australia. She pointed out that Rifai considered Morchella species in general to represent “aggregate species” as has been borne out in molecular phylogenetic studies. Gamundí’s collection has somewhat swollen but not capitate acroparaphyses. At about 54.87820°S, 67.32861°W, this specimen from Tierra del Fuego represents the southernmost occurrence of a species of Morchella in the world. An unverified record of M. semilibera from the Falkland Islands is discussed by Pegler et al. (1980), but at a lower latitude. The species identification for both remains problematic; as members of the highly diverse Elata clade, sequence data is needed to give precise identifications. There are a number of additional unverified records of Morchella species (mostly M. conica and M. elata) in South America. Ultimately, DNA sequencing will determine whether additional species are present, as the names formerly applied cannot be easily mapped onto modern concepts.
One particularly enigmatic species name, Morchella patagonica Spegazzini (1909), was based on material from Puerto Blest, Nahuel Huapi, Argentina collected in December 1904. Of note in the original description are Spegazzini’s (1909) comments that the asci become blue in iodine, the ascospores have two small guttules and the hymenium lacks paraphyses. These characters are anomalous in the genus Morchella. Spegazzini (1912) collected the species once again from Las Juntas, Catamarca, Argentina, in April 1910. For this specimen, he again noted the bluing of the asci in iodine, but this time described the spores as eguttulate. Gamundí (1964) reexamined the type specimen held at LPS in Spegazzini’s herbarium. While she did note the guttules in the spores and the apparent lack of paraphyses, her examination did not reveal bluing in the hymenium, only the development of a reddish-purple shade. Unusually, she also describes that the ascospores have pointed ends. Both of Spegazzini’s specimens were apparently examined by Dominguez (1987), but with very few morphological observations given; she does not, however, mention the asci bluing in iodine. There also seem to be no reliable modern collections, with only the type collection being listed by Gamundi et al. (2004). Given the inconsistency in the descriptions and that we have not reexamined the original material, we feel this name is better treated as a nomen ambiguum. We note, however, that we have an anamorph collection of M. andinensis/Mel-37 (MES-1185) from Puerto Blest, the locality indicated by Spegazzini (1909) for M. patagonica. This provides circumstantial evidence that M. andinensis might be a later name for M. patagonica, but without critical study the question remains unresolved.
The name Morchella intermedia Boud. was first applied in South America by Gamundí and Horak (1995). Their illustrations make it clear this name was used for a member (or members) of the Elata clade. This is broadly in keeping with Boudier’s concept of the species, which was based on an illustration of M. conica by Krombholz. This name has been used by some other authors more recently (Gamundí et al. 2004, Wright & Albertó 2006, Molares et al. 2020), but given that it has not appeared even in the recent taxonomic literature on European morels, it should likely be replaced in the South American Funga with one or more of the Elata clade morels that were detected in this and other molecular studies.
Another set of intriguing reports of South American morels are a series of reports of apparent members of the Esculenta clade from Chile, northern Argentina and southern Brazil. Not much can be made of a 1929 report from Chile (Espinosa 1929), but more recent reports give better evidence that the Esculenta clade members are present in southern South America. Dominguez (1987) described collections she referred to M. esculenta from around the Villa Allende and Villa Warcalde, near Córdoba, Argentina. Two ascocarps were from grasses around fruit trees and two others were on soil near a grove of cultivated and native trees; all are preserved in CORD. Dominquez (1987) thought her collections were closest to M. patagonica, the type specimen of which she had studied. She pointed out, however, that the anomalous characters of M. patagonica reported by Spegazzini (1909) – guttulate ascospore and the lack of paraphyses – were absent in her collections. Dominguez (1987) also provides a key which includes M. conica (from Río Negro and Chubut), M. elata (from Neuquén and Tierra del Fuego), M. esculenta (from Córdoba) and M. patagonica (from Catamarca and Río Negro). Mahú (1987) reported an immature collection he referred to M. vulgaris from the coast near Santiago, Chile. The ascoma was collected among herbaceous plants near the edge of native scrub, Mahú provided illustrations and some description. Spegazzini (1918) had also reported M. conica from Chile which he found to be no different than those from Argentina. Nozari and de Souza (1995) reported three ascomata they referred to M. esculenta from Rio Grande do Sul, Brazil, from a residential garden, and provided a description; the specimens are preserved in HURG. Cortez et al. (2004) also reported a collection of M. esculenta from Rio Grande do Sul, Brazil (preserved in SMDB), this collection in a forest among mosses under an orange tree; they provide illustrations and a description. Sobestiansky (2005) reported a collection of M. esculenta from the same state from mixed soil. The specimen is preserved at MBM. Morchella esculenta is also reported from Argentina by Daniele and Becerra (2013) and Dominguez et al. (2021). Their collections come from Tucumán, where they were collected under alders. These collections are preserved in CORD. Vignale et al. (2022) provide a description and several specimens from the Province of Misiones in the Paranaense Forest ecoregion of the Atlantic Forest. They provide morphological comparisons with the species previously reported in southern South America. Furci (2013) also reports M. esculenta from central Chile. These published reports are joined by a number of online and herbarium reports, including even a potential member of the Rufobrunnea clade from Argentina. Efforts should be made to place these morels in the modern classification of the genus.
Molares et al. (2020) studied the wild edible fungi as used and understood by the Mapuche people of Patagonia. They observe that: M. tridentina, M. eximia (as M. septimelata) and an unidentified morel (presumably M. andinensis) have great cultural value. These three species had the highest relative frequency of mention and were among the main market species along with Suillus luteus and Cyttaria espinosae. The morels were among the fungi favored for consumption within the community and commercial harvest and are a relatively new seasonal but significant source of income (Valenzuela-Flores 2003). In an earlier study in Peru (Franquermont et al. 1990) three species of Morchella, M. deliciosa, M. elata, and M. esculenta, were reportedly consumed by the Chinchero community in Andean southern Peru.
Our data indicate that the two species most frequently found in the marketplace were M. tridentina and M. andinensis, which do not occur with burns. This agrees with the findings of Gerding et al. (2022). The fire adapted species Morchella eximia was not found in our market samples at all; the one ascomatal collection of M. eximia we include was from a pine plantation after a fire. Intentionally set fires have been used to promote Morchella fruiting (Pfister 2016; Furci 2019, https://ffungi.org/eng/campaigns/). That our samples did not contain the fire induced species may be a positive indication that intentional burning of Nothofagus forests used to trigger harvesting of morels is futile, given the non-fire dependent nature of the native morels found in Chile and Argentina. It may also indicate that the sustainable harvest of M. andinensis and M. aysenina is sufficient for the Argentine and Chilean morel trade, since supplementation of harvest by burning forests is not supported by our results. Guidelines for sustainable and responsible collecting of morels are given by de Michelis and Rajchenberg (2006) and Pavez Andrades and Muchuca et al. (2022).