Aloina aloides var. ambigua (Bruch & Schimper) E. J. Craig = Aloina ambigua
(Note: many bryologists recognize Aloina ambigua as a distinct species, whereas the Flora of North America recognizes it only as a variety of Aloina aloides)
Aloina aloides var. ambigua is a tiny (2.5 mm) acrocarpous moss, with thick, strap-shaped, fleshy leaves arranged in a rosette, giving the impression of a miniature aloe plant. The margins of the leaves are seriously incurved, partially obscuring the finger-like photosynthetic filaments which cover the leaf surface. Sporophytes are tall (5-13 mm), with a cylindrical capsule, and long twisted peristome teeth atop a basal membrane. Plants may be scattered or in crowded turfs, typically on flat, compact, sandy or gravelly soil, in partial shade or full sun.
Scroll down for more photos (click to enlarge) and descriptions of habitat, plants, leaves, sporophytes, distribution map, name origin, and similar species.
Habitat: Aloina aloides var. ambigua grows on mineral soil in partial shade or full sun.
Habit: Aloina aloides var. ambigua may be found as scattered plants, or in dense patches.
Plants: Each Aloina aloides var. ambigua plant has just a few leaves arranged in a flattened rosette, perhaps 1 mm high. When fertile, the tall, straight sporophytes add another 3-5 mm in height. When dry, the leaves curl up and plants appear as brown nubs.
Leaves: Aloina ambigua leaves are strap-shaped (ligulate) or tongue-shaped (lingulate), 1-2.8 mm long, with inrolled margins partially covering a layer of finger-like photosynthetic filaments (lamellae) arising from the midrib (costa). The leaf tips are blunt and rounded, with the costa rarely projecting beyond it. The leaf base is thinner and sheathing, with flat margins which reportedly do not have a clear border (limbidium), that is, there are not several rows of significantly longer and thinner walled cells along the edge. The Moss Flora of Mexico states that the marginal cells may be bleached. In my experience, there are one or two rows of cells that are indeed bleached (hyaline) and do have thinner walls than those of the interior cells, but are not typically longer and narrower.
Sporophytes: Aloina aloides var. ambigua sporophytes tower up to 13 mm above the plants, with stalks (setae) that are overall straight, but which regularly twist to the left at the base and then to the right near the capsule, according to the authors of the Moss Flora of Mexico, and indeed I have seen this to be the case. The capsules are cylindric, up to 3 mm long, and if they manage to make it to maturity, will have a set of long (600-1200 µm), twisted teeth (peristome), which on close inspection (400x) are seen to be atop a basal membrane a few cells tall. Before fully mature, the peristome teeth are covered with a lid (operculum) which is long and beak-like (rostrate).
Male plants: Aloina aloides var. ambigua is dioicous, with separate male and female plants, or apparently sometimes rhizautoicous, with males attached to females via rhizoids. Males can be spotted by the presence of an orange-brown mound in the center of the rosette. These are the sausage-like antheridia containing sperm, interspersed with sterile finger-like paraphyses.
Distribution:
Bryophytes of Santa Barbara 