Anthoceros fusiformis Austin
Description: Anthoceros fusiformis is a hornwort that forms rather frilly, light green rosettes, composed of strap-shaped branches with wavy margins (dissected or crisped), and many flap-like outgrowths (lamellae) of varying sizes on the upper surface. The thallus is quite thick near the center, expanded by internal cavities filled with air or mucilage, and by large black, spherical colonies of the cyanobacteria Nostoc. As in all hornworts, cells of the thallus have one large chloroplast per cell. Chloroplasts have starch-free regions, though in my limited experience these are visible only in more mature plants.
Anthoceros fusiformis is monoicous, with individual plants bearing both female and male reproductive organs, and consequently is commonly found with sporophytes, the horn-like structures. Sporophytes are very tall (4 cm to over 10 cm), and at maturity turn black at the tips, as the capsule splits open to release the black spores. Spores are 42-58 (or 33-62) μm, with black spines on the distal face, and papillae on the proximal faces, with the exception of a narrow smooth strip along the triradiate ridge.
Anthoceros fusiformis is typically found on exposed soil in shaded areas along trails, road cuts or creeks, but can also be found on rocks and in sunnier areas in seeps.
Key Characters:
- Thallus: rosettes of overlapping strap-shaped branches, inflated by large cavities within, upper surface covered with many flap-like lamellae
- Tubers: none
- Sporophytes: 4-10 cm or even 16 cm long
- Spores: dark brown or black, distal face with spines, proximal face with shorter spines, but with a smooth strip along the triradiate ridge
- Chloroplasts: usually 1/cell, with starch-free zones in center
Scroll down for photos illustrating habitat, form, macroscopic and microscopic features such as lamellae, cavities, chloroplasts, spores (click to enlarge) .
Bryophytes of Santa Barbara 