Bryophytes of Santa Barbara

Hennediella stanfordensis (Steere) Blockeel

Hennediella stanfordensis is a small (0.5-1 cm), somewhat ephemeral, acrocarpous moss, with a rather floral look. Plants are translucent medium green when thoroughly wet, but quickly become a lighter, brighter, matte green when merely moist. Leaves are elliptic with a sturdy costa, distinctive stout teeth at the apex, and a bistratose border made up of long papillose cells. Hennediella stanfordensis thrives in ruderal areas with a fair amount of human disturbance, but can also be found in coastal sage scrub or chaparral.

Scroll down for more photos (click to enlarge) and descriptions of habitat, plants, leaves, distribution map, and name origin.

Hennediella stanfordensis — Hennediella stanfordensis, plants in middle right are thoroughly wet and translucent medium green, surrounded by merely moist, matte light green plants (CAH #1079, #1123, #1200). CC BY-NC Amanda Heinrich

Habitat: Hennediella stanfordensis thrives in ruderal areas with a fair amount of human disturbance, such as along trails, and at rest areas and playgrounds, but it can also be found at the base of shrubs in coastal sage scrub or chaparral, in partial shade or full sun.

Hennediella stanfordensis — Hennediella stanfordensis moist on soil in coastal sage scrub, (CAH #1079, #1123, #1200). CC BY-NC Amanda Heinrich

Hennediella stanfordensis — Hennediella stanfordensis dry on soil in coastal sage scrub, (CAH #1079, #1123, #1200). CC BY-NC Amanda Heinrich

Habit: Hennediella stanfordensis tends to form low, loose carpets in areas of high human disturbance. In more sheltered sites, Hennediella stanfordensis may form denser, taller cushions, which tend to be less ephemeral, with plants persisting for years.

Hennediella stanfordensis — Hennediella stanfordensis dense cushion moist (CAH #1079, #1123, #1200). CC BY-NC Amanda Heinrich

Hennediella stanfordensis — Hennediella stanfordensis dense cushion dry (CAH #1079, #1123, #1200). CC BY-NC Amanda Heinrich

Plants: Hennediella stanfordensis plants growing in loosely scattered populations tend to have an open floral rosette appearance, with larger oblong leaves spreading horizontally, revealing the budlike smaller perichaetial leaves in the center, which tightly surround the archegonia. In tighter cushions, the leaves tend to be more upright, giving the appearance of a flower just beginning to open. Plants are translucent medium green when thoroughly wet, but quickly become a lighter, brighter, matte green when merely moist. When dry, leaves curl revealing the sturdy costa and bistratose margins in a twisted wired ribbon look.

Hennediella stanfordensis — Hennediella stanfordensis moist plants densely packed with leaves slightly upright (CAH #1079, #1123, #1200). CC BY-NC Amanda Heinrich

Hennediella stanfordensis — Hennediella stanfordensis dry plants with leaves curled like wired ribbons (CAH #1079, #1123, #1200). CC BY-NC Amanda Heinrich

Hennediella stanfordensis — Hennediella stanfordensis plants moist, leaves spread (CAH #1200). CC BY-NC Amanda Heinrich

Hennediella stanfordensis — CC BY-NC Amanda Heinrich plants dry, leaves curled (CAH #1200). CC BY-NC Amanda Heinrich

Hennediella stanfordensis — Hennediella stanfordensis plants moist, leaves spread (CAH #1200). CC BY-NC Amanda Heinrich

Hennediella stanfordensis — Hennediella stanfordensis plants dry, leaves curled (CAH #1200). CC BY-NC Amanda Heinrich

Leaves: Hennediella stanfordensis leaves are oblong to elliptic, 2-3 mm long, with a sturdy costa ending in a serious snaggle tooth, visible in the field with a decent hand lens. The apex of the leaf has several additional large, menacing teeth. Both the upper and lower surfaces of the leaf cells are covered with a dense layer of c-shaped bumps (papillae), contributing to the matte appearance of plants when merely moist. The leaf border is quite unusual in that it is composed of two layers (bistratose) or more (multistratose) of long, narrow cells, which are also papillose.

Hennediella stanfordensis leaf — Hennediella stanfordensis leaf, 100x, images stitched, (CAH #1200). CC BY-NC Amanda Heinrich

Hennediella stanfordensis leaf — Hennediella stanfordensis leaf, 100x, images stitched, (CAH #1200). CC BY-NC Amanda Heinrich

Hennediella stanfordensis leaf tip — Hennediella stanfordensis leaf tip with snaggle teeth, 400x, (CAH #1200). CC BY-NC Amanda Heinrich

Hennediella stanfordensis leaf margin — Hennediella stanfordensis leaf margin, comprised of long, narrow, papillose cells, 400x, (CAH #1200). CC BY-NC Amanda Heinrich

Hennediella stanfordensis leaf cross-section — Hennediella stanfordensis leaf cross-section, 400x, (CAH #1200). CC BY-NC Amanda Heinrich

Hennediella stanfordensis leaf margin cross-section — Hennediella stanfordensis leaf cross-section, revealing bistratose/multistratose leaf margin, 400x, (CAH #1200). CC BY-NC Amanda Heinrich

Sporophytes: Sporophytes have not been seen on Hennediella stanfordensis within California. Most plants I have examined have several archegonia with eggs, apparently waiting in vain for sperm, which never arrive. The species is dioicous, with separate male and female plants, but I have yet to come across a male. I became somewhat obsessed with the question of how an ephemeral moss which does not produce sporophytes manages to replicate itself year after year, and wrote an article about my investigations for Bryolog, the quarterly newsletter of the California Native Plant Society Bryophyte Chapter.

Hennediella stanfordensis archegonia — Hennediella stanfordensis archegonia amongst small inner leaves, 100x, (CAH #1200). CC BY-NC Amanda Heinrich

Distribution:

Hennediella stanfordensis collections. Map generated by google maps using data from the Consortium of Bryophyte Herbaria of accessioned collections from herbaria.

Name

The genus Hennediella is named for Roger Hennedy, a Scottish phycologist who lived from 1809-1877. The species was first identified on the grounds of Stanford University, hence the species epithet, stanfordensis.

References and Further Reading

Hennediella stanfordensis, Richard H. Zander, Flora of North America Vol. 27

California Mosses, Bill and Nancy Malcolm, Jim Shevock and Dan Norris. Available for purchase from the California Native Plant Society here.

Contributions toward a Bryoflora of California II. A Key to the Mosses, Daniel H. Norris and James R. Shevock, Madrono 51(2): 133-269. 2004. Available for purchase here.

Hennediella stanfordensis/Tortula brevis, British Bryological Society Field Guide