Observation 105844: Geastrum Pers.
When: 2012-08-18
No herbarium specimen
0 Sequences

Yay, I found an earthstar!

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By: Steph Jarvis (Steph Jarvis)
2012-09-02 12:01:31 PDT (-0700)

If you have the material, I would take a look at the spores and measure them. Then I would look for the presence, or absence of the apophsis: the stalk upon which the sac sits on – it should be completely absent in G. saccatum. They both will have revolute rays with trash collected on the base, for the most part. These things should put you to the right name.

The difference between G. fimbriatum and G. saccatum:
By: Steph Jarvis (Steph Jarvis)
2012-09-02 11:58:22 PDT (-0700)

Geastrum fimbriatum Fr.:
Gasterocarp 15-35 m wide x 15-30 mm height. Exoperidium splitting into 5-10 rays, and tips splitting again occasionally. Saccate endoperidium, rays arching and revolute. non-hygroscopic. Mycelial layer thin & present. heavily encrusted with debris, or occasionally or only lightly. Pseudoparenchymatous layer medium thick, often orange in color, drying thin becoming rimose, especially at the tips of the rays, leaving patches on older specimens. Endoperidial body grey orange to light brown, with no apophysis or reduced, stalk up to 2mm if present. Peristome finely fibrillose, broadly conical & truncate. Gleba yelloish to brown & cottony. SPORES: 3.2/4- 3.2/4u, globose, verrucose with truncate verrucae, central oild drop present, pedicel rudimentary & hard to tell from verrucae. EUCAPILLITIA: “geastrum” type. 2.4-7.2u wide, thick-walled. Glabrous and lightly encrusted, unbranched, attenuate at the tips. Lacking pores, lacking septa. Lacking sphaerocysts in the endoperidial tissue.

Geastrum saccatum Fr.:
Gasterocarp larger than above: 30-60 mm wide x 15-25 mm height. Expperidium splitting to the middle or more, forming 6-8 rays, narrow to truncate rays, splitting at the tips often. Rays saccate, or revolute with rays rolling under the gasterocarp, occasionally having some revolute rays and others involute. Non-hygroscopic. Mycelial layer thin, persistent, membranous, not encrusted with debris or very lightly so. Pseudoparenchymatous layer becomming dark brown from pallid or grayish orange. thin. peristent, rarely forming a collar (as seen in G. triplex). Endoperidial body 15-30mm wide x 5-10mm height, including peristome. sessile, globose, depressed golobose to broadly ovate. Apophysis absent. Stalk absent (so truly the endoperidial gleba is saccate within the rays, whereas fimbriatum most often has an apophysis or stalk lifting it up out of the rays), Peristome finely fibrillose, distinct with a distinct ridge & up to 2 mm in height. Gleba dark brown & cottony. SPORES: larger than fimbriatum: (4.0) 4.8/5.6u – (4.0) 4.8/5.6u, verrucose with truncate verrucae, central oil drop present, pedicel again rudimentary and difficult to discern from verrucae. Sterigmal remnants absent from water mounts (is often the case with this group, but is present in some Vascellum). EUCAPILL: “geastrum” type, 4.0-9.6u wide, thick walled, lightly encrusted, unbranched, or occasionally short, rudimentary branches. Threads straight, occasionally subundulate, attenuate at the tips, lacking pores, aseptate, elastic. Spaerocysts absent in endoperidial tissue.

what’s the difference between
By: Dmitriy Bochkov (convallaria)
2012-08-19 11:50:35 PDT (-0700)

Geastrum fimbriatum and Geastrum saccatum? And which one is this?

Created: 2012-08-18 09:30:11 PDT (-0700)
Last modified: 2012-09-02 11:58:47 PDT (-0700)
Viewed: 42 times, last viewed: 2017-06-13 18:19:40 PDT (-0700)
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