Familia: Mniaceae ⇾Genus: Leucolepis ⇾Species: Leucolepis acanthoneuron
Genus name: Leucolepis Lindb. leucolepis umbrella moss (no Japanese name, as this moss doesn’t grow in Japan)
About genus: According to USDA classification Leucolepis Lindb. – leucolepis umbrella moss genus contains only 1 Species: Leucolepis acanthoneuron (Schwägr.) Lindb. – leucolepis umbrella moss.
The name Leucolepis is derived from Greek leuco = white, and lepis = scaly, alluding to scale-like stem leaves.
Species description: Leucolepis acanthoneuron is one of the most easily recognized of mosses, as it’s truly dendroid (tree-like) – when held up it looks like a miniature palm tree. Plants are 3-8 cm tall, grow in in a grove of treelets – in tufts or mats, with erect stems reddish brown to black, branched on the top. Leaves are pale green (on young plants) to dark green, sometimes reddish brown, spreading on top of the stem.
The Native peoples used this plant as a dye.
Synonym(s): Leucolepis menziesii (Hook.) Steere in L. Koch
Common names: tree moss, Menzies’ tree moss, umbrella moss, white-scaled tree moss. Also known as Leucolepis umbrella moss.
Attention: Many common names for mosses can be misleading as they are shared by different species, even genera: to make sure you are searching for a specific moss, refer to its Latin name, if known.
Habitat: Common on moist soil, rotten logs, and tree trunks, shaded habitats along streams, in lowlands and forests. In British Columbia it is found in swampy areas on logs, boulders, and earth. It is also epiphytic (living on the surface of plants) on deciduous trees, particularly Acer macrophylum and Quercus douglasii.
Leucolepis is very shade-tolerant, but it’ll tolerate full sun in a boggy ground.
Distribution: Menzies’s tree moss is a western North American endemic, common in coastal areas from sea level to subalpine elevations; it grows in British Columbia, Washington, Oregon, Idaho, Alaska, California.
SJG notes: The best place in the Seattle Japanese Garden to observe Mienzies’ tree moss is on the NW corner of ZZW, where an established colony of irregular shape reaches the size of outstretched hands (about 2 meters). There are smaller, younger colonies sizes of dinner plate (about 18 cm) and dark green in color of Leucolepis acanthoneuron in the middle of ZZW hill, but they are not visible from the path.
When I took the first pictures of the colony on the hill in the early June of 2015 it was thriving and its top leaves were so long they nearly curled into ringlets: younger, green specimens mixed with brown older ones made it appear as if the hill was covered with giant spiders.
The colony looked healthy for the entire next year, displaying the same mixture of young and old plants, until the scorching summer of 2016 turned it into unsightly shriveled dark brown and black mess, with no young plants to look at for half a year.
Then in January of 2017 the colony that looked quite dead started to sprout new green pokes, which soon turned to look like mini-fronds and by the end of February some of them filled in, and look like miniature palm trees – which means that the colony survived after all.
It’ll be interesting to observe how this new plants fill on top of the dead ones: I’ll post later in the year pictures.
References and related reading:
• Comprehensive report on Leucolepis acanthoneuron from NatureServe Explorer
• Good description and nice drawing of the plant from Missouri Botanical Garden
• Very clear picture of single Leucolepis acanthoneuron plant at iNaturalsit.org
• Page on Leucolepis from University of California herbarium
• Mienzies’s tree page from Kanaka Creek Regional Park at the Project Noah – crowd-sourced citizen-scientist website
• Literary reference – for moss gardeners:
Leucolopis acanthoneuron is a moss of American continent Pacific coast range only, so not mentioned in many books about moss. But it appears in a book by a local writer George Schenk, who used to run landscaping and nursery business in Seattle. On page 209 in his ‘Moss Gardening. Including Lichens, Liverworts and Other Miniatures’ book he advises that ‘this species transplants with ease into humusy shade garden. It is a first-rater among those mosses whose spread is not large, not small, but moderate’. Earlier in the chapter he writes that it’ll ‘extend into a small-scale ground cover about the size of a scatter rug’ […].