North American Fungi. 13 



peridium up into the air ; the inner peridium remains seated at the 

 center of the expanded outer peridium with the segments ranged 

 around it like a star. Three layers may be distinguished in the struc- 

 ture of the outer peridium ; first, the epidermis or cuticle, usually flaky 

 and fragile ; second, the middle fibrillose layer consisting of stout, 

 closely woven hyphae, running in the direction of the surface; third, 

 the inner fleshy layer, thick when fresh and growing, but shrinking 

 much in drying. The fibrillose layer is continuous at the base with 

 the inner peridium, which has a similar structure, and projects into 

 it as the columella; when the fleshy layer is quite thick, the connec- 

 tion between the two appears as a short pedicel after the former has 

 shrunk in drying. 



TABLE OF SPECIES OF GEASTER. 



§1. DEPELLITI. Peridium depressed-globose, not pointed ; the 

 segments acute at the apex. 



I. Pedicellati. Outer peridium conspicuously vaulted under- 

 neath ; inner peridium with a distinct pedicel. 



a. Mouth sulcate-plicate 1, 2, 3. 



b. Mouth ciliate-fimbriate 4, 5, 6. 



II. Sessiles. Outer peridium with the base convex, not vaulted ; 

 inner peridium sessile. 



c. Mouth sulcate-plicate 7. 



d. Mouth ciliate-fimbriate 8. 9. 



e. Mouth dentate or lacerate 10, 11. 



§2. PELLICULOSI. Peridium ovoid, pointed: the segments 

 acuminate at the apex. 



III. Saccati. Outer peridium with the base saccate; inner perid 

 ium sessile. 



/. Mouth sulcate-plicate 12. 



g. Mouth ciliate-fimbriate 13, 14, 15. 



>§i. DEPELLITI. Peridium depressed-globose, not pointed ; the seg- 

 ments acute at the apex. The peridium is at first sunk deep in the soil 

 and connected with it by an abundant filamentous mycelium, which 

 issues from every part of the surface ; at maturity, when the outer 

 peridium expands its segments, the mycelium being held fast by the 

 soil, strips off the cuticle from the fibrillose layer. 



I. Pedicellati. Outer peridium multifid, becoming wholly reflexed 

 and conspicuously concave or vaulted underneath, often lifted up on 



