COMMENTS—The Disciseda group can be confusing due to similarities among the taxa; grey endoperidium, sand case, and small stature. Disciseda cervina is distinctive by the fimbriate ostiole, occasional grayish purplish tint to the endoperidium, verrucose spores, lacking paracapillitium, and sometimes having a small pedicel on the spores. In comparison, Disciseda candida can be distinguished macroscopically by the reticulate pattern along the basal portion of the endoperidium, microscopically by the presence of paracapillitium, and lacking a pedicel on the spores. In addition, D, cervina has a dark brown to reddish brown powdery gleba when mature, whereas D. candida has a dark brown to purple brown powdery gleba when mature. Disciseda anomola, a common species in North America, but not reported from California, has a tubular ostiole with smooth to asperate spores that lack pedicels, separated from Disciseda candida and Disciseda cervina by having larger spores and a more prominent ostiole. Disciseda cervina seems more common in California than Disciseda candida. Although reported in the literature, the rolling over nature of Disciseda remains to be seen and verified by this author. The ITS data here supports this species within a Disciseda clade with 84% bootstrap and 98% PP.
NOTES ON GENUS:
Disciseda Czern., Bull. Soc. Imp. nat. Moscou 18(2, III): 153. 1845.
TYPE—Disciseda collabescens Czern. [as ‘collabascens’], Bull. Soc. Imp. nat. Moscou 18(2, III): 153. 1845.
Disciseda was erected by Czerniaiev in 1845, but his work was not well known at the time. Several species of Disciseda remained in Bovista until 1892, when Morgan segregated those with a basal sand case into a new genus, Catastoma. In 1903 Dr. L. Hollós recognized this duplication of efforts and transferred many species of Catastoma into Disciseda (Lloyd 1906). Zeller (1947) described several new species of Disciseda, transferring some of them from Catastoma, of which most of these originate from California. Catastoma means mouth down, as is the very nature from which the stoma develops in many species. On the grounds of priority, Disciseda is the oldest valid generic name.
The development of the stoma in Disciseda is a unique feature. Many mycologists (Lloyd 1903, Lohwag 1930, Coker and Couch 1928, Ahmad 1950, Mitchel et al. 1975) argue that the stoma develops as the fruitbody matures, rolls over, and is torn from a basal attachment off of a rhizomorph or mycelium tuft that remains in the substrate. Hence, the bottom becomes the top in this rolling over manner. Most species grow subhypogeous to hypogeous, and to this day little is known about the early fruitbody development of this group of fungi. This unique and very small globose to ovate puffball does not always have a basal opening. Several species develop an apical stoma in the usual manner (Coker and Couch 1928, Ahmad 1950, Mitchel et al. 1975).
However, in the case of Disciseda cervina, Ahmad (1950) surveyed hundreds of specimens and observed them in a natural setting for several days. His findings described the exoperidium sand case eroding from the base upwards until only an apical cap remained. As the fruitbody matured, the rhizomorph remained attached at the base, keeping the fruitbody in place in the soil. Ahmad reports that after ten days, the fruitbody appeared gelatinized at the base and the rhizomorph was easily pulled out leaving a pore, or stoma, in its place. The wind typically worked the fruitbody of Disciseda cervina out of its original location, rolling it over, and the bottom became the top with the new stoma at the apex. Disciseda can be collected in arid grass landscapes, in sandy dune habitats, and in areas with constant dry and windy conditions. When collecting fungi from this genus, it is important to treat each individual fruitbody as an individual collection. Terrain in which Disciseda is found may have a variety of species, making mixed collections possible.
The genus Disciseda currently has thirty-seven species that have been recorded in Index Fungorum, fourty-six including all varieties. Disciseda collabescens Czern. is the type species of the genus. There are nine species reported from California: D. atra, D. brandegeei, D. candida, D. cervina, D. levispora, D. luteola, D. subterranea, D. uplandii, D. johnstonii.