Geastrum complanatum Dourado-Barbosa, R. L. Oliveira, A. A. Lima, P. Marinho, Baseia & R. Cruz, 2025

Geastrum complanatum Dourado-Barbosa, R. L. Oliveira, A. A. Lima, P. Marinho, Baseia & R. Cruz , sp. nov.

( Fig. 3 View FIG )

DIAGNOSIS. — Geastrum complanatum sp. nov. is characterized by presenting fornicate basidiomata, discrete apophysis, flattened pedicel, and a “farinaceous” crystalline matter on the endoperidial surface, with pupa-shaped (pupiform) crystals under SEM.

ETYMOLOGY. — Based on the flattened shape of the pedicel.

MATERIAL EXAMINED. — Brazil • Bahia, Barreiras, Família Barbosa Farm, Cerrado stricto sensu; found on termite mound in a gregarious growth; 12°7’11.25”S, 45°4’26.43”W; 13.IV. 2020; K.D. Barbosa , KD0038; Holotype: BRBA-Fungos 0027 ; GoogleMaps Isotype: UFRN-Fungos 3677 . GoogleMaps

HABIT. — Gregarious, growing on termite mound

MYCOBANK. — MB#849825.

GENBANK ACCESSION NUMBER. — OR479886 (ITS), OR479888 (LSU).

Geastrum biplicatum Berk. & M. A. Curtis Geastrum glaucescens Speg. Geastrum meridionale J. C. Zamora Geastrum papinuttii J. C. Zamora Geastrum parvistriatum J. C. Zamora & Calonge Geastrum plicatum Berk. Geastrum pectinatum Pers. Geastrum striatum de Candolle

Geastrum tenuipes Berk.

Geastrum complanatum sp. nov. Exoperidium 34 mm diam., with 7 non-hygroscopic rays 18-45 mm diam., with 6-8 non-hygroscopic rays 45-125 mm diam., with 5-12 non-hygroscopic rays 12-24 mm diam., with 6-11 non-hygroscopic rays (13-)19-47 diam., with 5-12 non-hygroscopic rays 38-62 mm 20-135 mm diam., with diam., with 6-9 non- (4–) 6-10 hygroscopic (–11) non-rays hygroscopic rays 21-85 mm diam., with (4–) 6-10 (–12) non-hygro- scopic rays 25-82 mm 17-28 mm diam., with diam., with 6-11 raios 7-11 nonnon- hygroscopic hygro- rays scopic rays Endoperidium 11 mm diam., dark brown, crystalline matter surface of COD bipyramidal crystals with 15.0 μm diam. 5-16 mm diam., dark brown to black, crystalline matter surface of COD bipyramidal crystals with 6.0-15.0 μm diam. 12-33 mm diam., cream to brownish grey, rarely dark brown, crystalline matter surface of COD bipyramidal crystals with 6.0-13.0 μm diam. 3.5-6.5 mm diam., mainly dark brown to black, crystalline matter surface of COD bipyramidal crystals with 6.0-12.0 μm diam. 5-16 mm diam., mainly dark brown to blackish, crystalline matter surface of COD bipyramidal crystals with 5.5-12.5 μm diam. 10-18 mm (4,5–) 10-25 diam., light (–36) mm to dark diam., dark brown, brown, crystalline crystalline matter matter surface surface of COD of COD bipyramidal bipyramidal crystals crystals with 7.0- with 5.0- 20.0 15.0 μm (–32.0) μm diam. diam. 5.5-26 mm diam., brown to black, crystalline matter surface of COD bipyramidal crystals with 5.0- 15.0 μm diam. 8-17 mm diam., grayish to dark brownish gray, crystalline matter surface of COD bipyramidal crystals with (20–) 25-55 μm diam. 5-13 mm diam., grayish brown, crystalline matter surface of COD pupallike crystals with (4.1–) 5.5-18.0 μm diam. Peristome Sulcate, slightly delimited, with 19 folds Sulcate, distinctly or not distinctly delimited, with 11-25 folds Sulcate, distinctly or not distinctly delimited, with (17–) 22-52 (–60) folds. Sulcate, distinctly or not distinctly delimited, with 12-20 folds Sulcate, distinctly or not distinctly delimited, with 7-23 folds Sulcate, Sulcate, distinctly distinctly or not or not distinctly distinctly delimited, delimited, with 16-30 with 11-35 folds folds Sulcate, sometimes well delimited, with 19-36 folds Sulcate, mainly well delimited, with 14-27 folds Slightly sulcate, sometimes well delimited, with 16-21 folds Pedicel Brownish, 2.0 mm in height Brown to dark brown, 0.5-2.5 mm in height Cream to dark brownish gray, (2.5–) 3.0-9.0 (–9.5) mm in height Brown to grayish brown, 0.5- 1.3 mm in height Brown to dark brown, rarely pale in color, 0.5-2.5 (–3.0) mm in height Light or dark Mostly light coloured, coloured, often very slender to slender, more or 3.5-6.0 mm less stout, in height (1.5–) 3.5- 13 (–15 mm White to Light or dark Yellowish brownish, coloured, white, 2,0- (1.0–) 2.0- very 3.0 mm in 9.0 mm in slender, height height 3.0- 7.0 mm in height in height Apophysis Not observed Not observed Not observed Not observed Not observed Not Not observed observed Well developed, solid, in ring shape with acute border Not observed Discrete, sulcate, color lighter than the endoperidium Capillitium Hyphae thick up to 10.5 μm diam. Hyphae thick, 6.0-9.0 µm diam. Hyphae thick, (5.5–) 6.0- 9.0 (–9.5) µm diam. Hyphae thick, 4.5-6.0 µm diam. Hyphae thick, (5.0–) 5.5-8.0 (–8.5) µm diam. Hyphae Hyphae Not Hyphae thick, thick, observed thick, 6.0-8.0 µm (8.0–)9.0-13.0 6.0-9.0 µm diam. (–15.0) µm diam. diam.

Hyphae thick, 3.0-6.0 µm diam.

DESCRIPTION

Unexpanded basidiomata absent. Expanded basidiomata fornicate, 14-30 mm high (including peristome), 17-28 mm wide. Exoperidium opening into 7-11 triangular rays, revolute, non-hygroscopic, fornicate. Mycelial layer cotonous, heavily encrusted, greyish white (1B1). Fibrous layer, papyraceous to coriaceous, persistent, pale yellow to greyish yellow (4A3, 4B3). Pseudoparenchymatous layer persistent, slightly rimose, collar absent, light brown (6D4). Endoperidium globose, 5-13 mm high (including peristome)× 10-13 wide mm, with “farinaceous” crystalline matter, and pupa-shaped (pupiform) crystals under SEM (4.1-18.0 µm diam.), greyish brown (6D3). Apophysis discrete, grooved, lighter than the endoperidium. Stalk/pedicel 2.0-3.0 mm high×3.0-6.0 mm wide, yellowish white (1A2), flattened. Peristome delicately/roughly sulcate, slightly darker than the endoperidium, 16-21 folds, 0.3-0.4 mm high. Gleba dark brown (6F4). Mycelial layer composed of hyphae, 1-2.5 µm in diameter, thick walled (0.4-1 µm), encrusted, slightly sinuous, unbranched, lumen evident, hyaline. Fibrous layer composed of coiled hyaline hyphae, 4.1-8.9 µm in diameter, thick-walled (1.9-4.1 µm), slightly encrusted, unbranched, lumen evident, slightly sinuous. Pseudoparenchymatous layers composed of globose to subglobose cells, hyaline, 19.3-54× 11.9-39.3 µm in diam., thin-walled (<1µm). Eucapillitium hyaline 3-6 µm in diameter, thin-walled (> 1 µm), non-encrusted, slightly sinuous, lumen evident, unbranched. Rhizomorphs absent. Basidiospores globose to slightly elliptical, yellowish to brownish (Q=1.00-1.25), 5.3-8.5×4.8-7.8µm [x=6.9±0.6 ×6.4 ±0.6, Qm =1.10, n=30], conspicuous ornamentation (0.2-0.9 µm in height) under LM, verrucose to irregularly pilate under SEM.

COMMENTS

Geastrum complanatum sp. nov. is a unique species growing unusually on the top of termite mounds in areas of the Brazilian Cerrado biome . The species is characterized by the presence of a flattened pedicel and “farinaceous” crystalline matter on the surface of the endoperidium, with the presence of pupa-shaped (pupiform) oxalate crystals under SEM, an exclusive crystal shape described for the first time for the genus Geastrum .

Phylogenetically, Geastrum complanatum sp. nov. fits with the representatives of Sect . Geastrum, Subsect. Sulcostomata , characterized by having species with grooved peristome, well-developed mesoperidium and powdery/pruinose layer formed by small crystals with generative hyphae on the surface of the endoperidial and pseudoparenchymatous layers ( Zamora et al. 2014; Zamora et al. 2015). In our phylogeny, G. complanatum sp. nov. groups in this Section and Subsection, together with G. meridionale J.C. Zamora (100 bs MP/ 52 bs ML/ 60 Bayesian pp), forming a sister-group with the species G. biplicatum Berk. & M.A. Curtis and G. tenuipes Berk. (100 bs MP/ <50 bs ML/ 59 Bayesian pp).

Geastrum complanatum sp. nov. morphologically resembles the specimens of G. pectinatum Pers. , G. meridionale , G. plicatum Berk. , G. glaucescens Speg. , G. parvistriatum J.C. Zamora & Calonge , G. papinuttii J.C.Zamora , G. striatum DC and G. tenuipes ( Table 2 View TABLE ), because all these species present a grooved peristome and the presence of crystalline matter on the endoperidial surface ( Zamora et al. 2015). However, the peristome of G. complanatum sp. nov. presents very discreet grooves and little development compared to the other species with grooved peristomes.

Geastrum pectinatum differs from G. complanatum sp. nov. by the presence of more robust basidiomata measuring 20-135 mm in diameter, while G. complanatum sp. nov. has delicate basidiomata measuring 17-28 mm in diameter ( Zamora et al. 2015). In addition, the endoperidium of G. pectinatum is formed by crystalline matter with calcium oxalate dihydrate (COD) bipyramidal crystals in the mesoperidium, with sizes ranging from 5-15µm in diameter ( Zamora et al. 2015), while G. complanatum sp. nov. has crystals that resemble a pupa, with sizes ranging from 4.1-18 µm in diameter. Geastrum meridionale J.C.Zamora is also similar to G. complanatum sp. nov., however the endoperidium of G. meridionale is much larger than that of G. complanatum sp. nov. specimens, with 12-33 mm in diameter and 5-13 mm in diameter, respectively. Furthermore, the exoperidium of G. meridionale is four times larger ( 45-125 mm in diameter) than that of G. complanatum sp. nov., with 17-28 mm in diameter ( Zamora et al. 2015).

Geastrum biplicatum resembles G. complatanum sp. nov. by the exoperidium with non-hygroscopic rays, brownish endoperidium with crystalline matter and a slightly delimited and sulcate peristome ( Zamora et al. 2015). However, G. biplicatum has crystals with bipyramidal shape measuring 6-15 µm in diameter, while G. complatanum sp. nov. has pupa-shaped crystals with (4.1-) 5.5-18.0 µm in diameter. Furthermore, G. biplicatum has a peristome with fewer folds (up to 19 folds), while the new species presented up to 21 folds.Two other species that are part of Subsect. Sulcostomata and resembles morphologically Geastrum complanatum sp. nov. are G. plicatum and G. glaucescens . However, the exoperidium of G. plicatum sp. nov. is a little more than twice the size of G. complanatum sp. nov., 38-62 mm in diameter, while G. glaucescens has pedicels that are commonly brownish, a characteristic not observed in G. complanatum sp. nov. which, in addition to presenting a yellowish white pedicel, has a flat conformation with up to 0.6 mm in diameter ( Zamora et al. 2015).

Geastrum parvistriatum and Geastrum papinuttii also resemble G. complanatum sp. nov. by the presence of farinaceous crystalline matter on the endoperidial surface and pedicellate endoperidium ( Zamora et al. 2015). However, both species have pyramidal COD crystals and do not have the pupal-shape observed in G. complanatum sp. nov. under SEM ( Zamora et al. 2015). The specimens of G. striatum and G. tenuipes also have morphological characters remarkably similar to G. complanatum sp. nov., such as the presence of a clear pedicel, farinaceous crystalline matter and globose basidiospores, however the exoperidium of the first two species is about three times larger, with diameters of 21-85 and 25-82 mm, respectively ( Zamora et al. 2015).