Gleba pale, filling the cavity. Capillitium interwoven, hyaline, tor- 

 tuous threads. Spores elliptical-fusiform, 8 x 16, hyaline, or pale 

 greenish color, rough. 



This has a strong, rooting base (Fig. 916), and was named Cas- 

 toreum radicatum. In its peridium, gleba, capillitium and spore 

 features it agrees with Diploderma, and should be united to this 

 genus. "Puff balls" are not classified by their "roots." It is known 

 from a couple of specimens at Kew collected at St. George's Bay, 

 Tasmania, by G. Wintle. One of the specimens, as shown in our 

 figure, is double, but that is probably not usual. The collector states 

 that the plant is "eaten by kangaroos and bandicoots." We con- 

 sidered this plant in our Lycoperdaceae of Australasia. It must be 

 a rare plant, and probably does not occur in Australia, for it never 

 reached me from any collector. 



DIPLODERMA SUBEROSUM. This was based on an immature specimen 

 (gleba not fully deliquescent), with a thick, pale exoperidium and a thin, black 

 endoperidium, no core, no sterile base. Capillitium scanty, hyaline. Gleba color 

 pale olivaceous. Spores globose, 4 mic. hyaline, very slightly rough. Only known 

 from a specimen collected by Broome, Brisbane, Australia. 



DIPLODERMA ALBA. This is extremely doubtful. It departs from the 

 idea of the genus in having a columella like some unopened Geasters. The type is 

 very immature, the gleba not yet deliquesced. Spores globose, hyaline. We should 

 consider it an unopened Geaster, but doubt if any Geaster, even immature, has 

 hyaline spores. Naturally, it is known only from the type locality, "Cudgegong 

 River, Australia." 



EFFETE MATTER. 



Diploderma fumosum, Cooke, Australia; Diploderma melasporum, Cooke, Australia; Diplo- 

 derma Ungerii, Schulzer, Austria; Diploderma tuberosum. Link, Germany, are unopened geasters. 

 Diploderma glaucum, Cooke, Australia, is Mesophellia arenaria. Diploderma sabulosum, Cooke. 

 Australia, and Diploderma pachythrix are Mesophellias, close, if not the same as Mesophellia arenaria, 



THE GENUS ARACHNION. 



The receipt of a "giant" Arachnion from Miss A. V. Duthie, 

 South Africa, has led us to a review of this curious genus. 



The genus can be briefly described as being puff-balls within 

 puff-balls. The entire interior of a ripe specimen is filled, not with 

 dust (spores and capillitium), as most puff-balls, but with a granular 

 substance that feels "gritty" when rubbed between the fingers. 

 These granules are peridioles, little sacks containing spores. They 

 are small, but can be seen undei a hand-glass, and even with the 

 naked eye. They are of the color, and appear as if the puff-ball were 

 filled with ashes. The name Arachnion refers "to a spider sac filled 

 with eggs." 



The genus Arachnion has always a very thin peridium with 

 a smooth cortex. It breaks irregularly, and is so fragile that it 

 is difficult to keep entire ripe specimens in the herbarium. There is 

 no sterile base. The gleba consists of little granular masses of spores 

 called peridioles, which in the type species are each surrounded with 

 an imperfect web of hyphae, analogous to the capillitium of other 

 "puff-balls," and for convenience called capillitium. In Arachnion 

 rufum, of Australia and in a form of Arachnion album from Brazil, 

 the peridioles are almost devoid of hyphae, almost naked, little balls 

 of spores. The spores are borne on slender sterigmata, which in some 



643 



