Small forms of Tetraplodon angustatus B. & S., and Splachnum ampullaecum Linn., closely resemble this species. The first, however, has a dimidiate calyptra, extending to the base of the sporangium, and only a monoicous inflorescence; the second has broader and less attenuated leaves, narrowed at the base, and an exserted capitate columella in the dried capsule: in both the apophysis of the capsule is much larger, particularly in the last, where it is of a deep purple color.
TAB. 58.—Tetraplodon australis.
1 . Plantæ naturali magnitudine.
2. Planta cum inflorescentia monoica.
3. 4. Folia.
5, 6. Areolatio basilaris et apicalis folii.
7. Capsula apophysata, pedicellus, et vaginula.
8. Sectio transversalis pedicelli.
9. Peristomium.
10. Ejusdem duo dentes adhaerentes.
11. Calyptra.
12. Operculum.
13. Flos masculus axillaris.
14. Antheridia et paraphyses.
