Berkeley's idea of the genus was expressed as follows: "Peridium naked or furfuraceous. Spores in groups, enclosed, at first, in a hyaline sack." Rostafinski, while accepting Berkeley's generic name, redefined it, emphasized the calcareous capillitium, and made reference to the spore-adherence only to assert that Berkeley's description was, in this particular, based on mistaken observation. In some species, the spores do, in fact, show a tendency to cling together, a characteristic which Badham was perhaps first to notice; but that this is occasioned by their being surrounded by a sac or common pellicle has not been proved nor even suggested, by any subsequent investigator. Berkeley's genus was therefore founded upon a slight mistake; but we may conserve his rights in the premises if we write Badhamia (Berk.) Rost., and so keep history straight.

Key to the Species of Badhamia

A. Spores ovoid or ellipsoidal
a. Spores free1. B. ovispora
b. Spores adherent2. B. versicolor
B. Spores spherical
a. Sporangia yellow
i. Spores free3. B. decipiens
ii. Spores adhering4. B. nitens
b. Sporangia grey, spores free
i. Always sessile5. B. panicea
ii. Stalked, at least some of them
O Stipe when present black
+ Globose, small .5 mm.6. B. affinis
++ Larger, spores strongly spinulose7. B. macrocarpa
+++ Discoidal or annulate8. B. orbiculata
OO Stipes membranous yellowish
+ Stipes long, sporangia iridescent9. B. magna
++ Stipes short or none; iridescent10. B. foliicola
c. Sporangia grey, spores adherent
i. Stipe when present yellowish
+ Wall iridescent, spores uniformly marked11. B. utricularis
++ More calcareous, spores strongly marked on one side12. B. capsulifera
+++ Colorado, spores anon barred13. B. populina
ii. Stipe when present black14. B. papaveracea
d. Sporangia brown, lilacine
i. Sessile15. B. lilacina
ii. Stipitate, columellate16. B. rubiginosa

1. Badhamia ovispora Racib.

Sporangia sessile depressed-globose or plasmodiocarpous, white or ochraceous, covered by dense calcareous scales; capillitium white, the lime-granules sometimes aggregate at the center to form a pseudo-columella; spores not adhering, brownish-purple ellipsoidal, 8 × 10–10 x 15 µ.

Reported from Bohemia, England, Pennsylvania.

2. Badhamia versicolor Lister.

Sporangia scattered or clustered, minute, .3–.5 mm., grey or flesh-colored, sessile, the calcareous deposits slight; capillitium white or apricot-colored; spores ovoid, 8 × 10–9 × 12 µ, clustered, purplish, and warted at the broader end, elsewhere colorless and smooth.