Geastrum violaceum Rick, Brotéria

Trierveiler-Pereira, Larissa & Da Silveira, Rosa Mara B., 2012, On the Geastrum species (Geastraceae, Basidiomycota) described by Rick, Phytotaxa 61 (1), pp. 37-46 : 43-45

Geastrum violaceum Rick, Brotéria 5: 26, 1906 [as ' Geaster violaceus ']. ( Figs. 5 , 6 )

= Geastrum episcopale F. Kuhar & L. Papinutti, Mycologia 101: 535, 2009, syn. nov.

Lectotype (designated here): — BRAZIL. Rio Grande do Sul, J. Rick, C.G. Lloyd’s Collection cat. no. 54722 (BPI 706193!).

Unexpanded basidiomata pyriform, fusoid to lageniform, apex acute; 1.1–2.1 cm high, 0.6–1.2 cm in diam.; mycelial layer light brown (6D4) to reddish brown (8 E4, 9 D4), with purplish and pinkish pigments; mycelial strands arising from the base, abundant, whitish to beige, up to 1.6 cm in length. Expanded basidiomata 1.0– 2.0 cm high (including peristome), 1.0– 1.9 cm in diam.; exoperidium saccate, rays 5–7, acute or not, involute, mycelial layer light brown (6D4, 7D4) to brown (6E5), fibrous layer pale orange (5A3) to grayish yellow (2B3), fleshy layer pastel pink (11A4), grayish rose (11B5), grayish red (10B5) to purple (15C6) when fresh, drying to dark brown (8F5) to reddish brown (8 E4, 8 E5); endoperidial body conical, globose ovoid to subglobose when fresh, sessile, 0.7–1.0 cm in diam., endoperidial surface asperulate, when recently exposed with a white pruina covering the surface, brown (7E4), reddish brown (8D4), light brown (6D4, 7D4) to brownish grey (10D2) when fresh, drying to dark brown (7F5, 6F4, 6F5); peristome fibrillose with few folds, concolorous with endoperidium or slightly lighter towards the apex, not delimited by color line or a groove; mature gleba olive brown (4 E3, 4 F5) to yellowish brown (5E4).

Mycelial layer hyphae thick-walled, 3.5–6 µm in diam., yellowish to hyaline, branched or not, simpleseptate, septum not always conspicuous, usually incrusted with amorphous material, lumen narrow and filled with reddish pink pigments; fibrous layer hyphae thick-walled or solid, 2–7 µm in diam., hyaline, rarely branched, incrusted or not, lumen narrow without reddish pigments; fleshy layer hyphae pseudoparenchymatous, mostly ellipsoid to subglobose (frequently collapsed in dried material), 11.5–54 µm in diam., yellowish, usually with reddish to pinkish pigments content; endoperidial hyphae thick-walled, 2–7 µm in diam., lumen narrow, yellowish to brownish, many of them enlarged at the apex, enlarged structures (mycosclerids) 6–17.5 µm in diam., fusoid, clavate to espathulate, yellowish to brownish; capillitial hyphae thick-walled or solid, simple-septate, 2–9 µm wide, lumen narrow, brownish, mostly incrusted, tapering towards the simple, rounded apex; basidiospores globose, 2.2–3.2 µm in diam., brownish yellow, finely punctate, ornamented with short, individual or confluent warts or columns; apiculus short, less than 1 µm long; basidia subglobose to ventricose with a long rostrum, 11–17.5 × 4–7 µm, hyaline, 8-spored.

Distribution and habitat: — Brazil ( Rick 1906) and Argentina ( Kuhar & Papinutti 2009, as G. episcopale ); found solitary or in small groups on soil.

Additional specimens examined: — BRAZIL. Rio Grande do Sul: Riozinho , on soil, April 2010, L. Trierveiler-Pereira 21 ( ICN) ; ARGENTINA. Chaco: Parque Nacional Chaco, May 2010, Hernández Caffot et al. (CORD 784) ; Corrientes: Curuzú Cuatiá , April 2007, L. Papinutti & G. Rolón (BAFC 51671, holotype of G. episcopale ) .

Remarks:— Geastrum violaceum is easily identified in the field due to its pinkish, purplish to violet fleshy layer contrasting to the brownish endoperidium. Its peristome is fibrillose, has a few folds and is not distinctly delimited.

G. violaceum has been a long forgotten name. After its original description at the beginning of the 20th century ( Rick 1906), the authenticity of this species was confirmed by Lloyd (1907), but was later synonymized with G. lloydianum by Ponce de León (1968). We are of the opinion, however, that the synonymy proposed by Ponce de Leon was not based on accurate morphological analysis of type specimens. Important features distinguishing G. violaceum from G. lloydianum are the pinkish, purplish to violet pigments present in the exoperidium, the subglobose to conical endoperidial body and the fibrillose peristome with few folds in G. violaceum . Rick described the species with delimited peristome, but after having examined the original material, we cannot agree with that. Even on dried specimens, including the lectotype, the presence of pinkish to purplish pigments in the exoperidium is preserved. The asperulate texture of the endoperidial body is due to the presence of mycosclerids formed by hyphae from the endoperidial surface.

Geastrum episcopale , recently described from Argentina ( Kuhar & Papinutti 2009), is a synonym of G. violaceum . G. episcopale was described with a smooth endoperidium, but we also found mycosclerids on the endoperidial surface of the type specimen.

According to Rick (1906, 1928), his collection of G. violaceum was sent to Lloyd. At herbarium PACA only one exsiccate is recorded as G. violaceum (PACA 9664, Fungi Rickiani 15973), but it is wrongly identified (the exoperidium has no purplish pigments and the basidiospores are much larger and with robust ornamentation).

Up to date, G. violaceum has only been reported from subtropical forests in South America ( Argentina and Brazil, lat. 29°S), but we also have seen pictures (courtesy of Douglas Eduardo Rocha) of the species from a fragment of the Atlantic tropical rainforest in the State of Minas Gerais ( Brazil, lat. 19°S). Unfortunately that material was not preserved, but it is our guess that the species also occur in tropical forests in South America .

Figures

FIGURE 5. Geastrum violaceum (A-E) and Geastrum episcopale (F). A. Unexpanded and expandaded basidiomata (BPI 706193, lectotype). B. Detail of the peristome with few folds (lectotype). C, D. Specimen in situ (L. Trierveiler-Pereira 21, ICN). D. Lateral view. E, F. SEM images of basidiospores. E. Lectotype. F. BAFC 51671, holotype. Photographs C and D by P.S. da Silva.

FIGURE 6. Microscopic structures of Geastrum violaceum. A. Mycelial layer hyphae (with reddish content). B. Fleshy layer hyphae (with reddish granules). C. Basidia. D. Capillitial hyphae. E. Mycosclerids from the endoperidial surface.