Cora den Hartigh returns with her second written entry. Cora scribes:
Poking through the Botany Photo of the Day Flickr Pool, I was thrilled to find photographers such as Don White (Don White@Flickr | original image) who also share my enchantment with the spindly and mysterious world of sporophytes. Thank you for appreciating little wonders!
This intriguing picture captures Rhizomnium glabrescens, commonly known as fan moss or large leafy moss. This is a common species along western North America’s coast from Alaska to California. It also occurs sparingly eastward into Montana. Prime habitat is on logs in coniferous woods on logs or areas with rich humus-y soil. This little bryophyte will cushion many a woodsy step! It is named for its smooth stems (Rhizomnium = “rhizoid-bearing moss”, glabrescens = “smooth”). The leaf blades or lamellae of Rhizomnium glabrescens are unistratose, or only a single cell layer thick. This lends a ghostly delicate quality to the lush mats formed by these mosses. Sunshine often renders them nearly transparent, like this! This moss is particularly dazzling in the dappled sunlight where it glimmers, particularly when it has collected water droplets.
Sadly, mosses haven’t garnered great interest from humans as useful plants. They are small and tend to have few economic uses. I was very excited, however, to find that Rhizomnium glabrescens was utilized as a poultice to reduce swelling by at least one First Nations group, the Makah.
A slightly curved operculum–the little cap at the tip of the sporangia–is diagnostic of this species; once mature and dry, the operculum will dehisce or pop off to expose rows of peristome teeth (yes, moss have teeth!!) which rely on the ambient humidity to move, flicking spores inside the sporangia outwards. UBC’s Biology 321 (Introduction to Bryophytes web site is the source of many of today’s links. The site has other excellent photographs of this species on this page: Rhizomnium glabrescens. This moss has a cute rosy seta, or stem-like structure, which stretches tall to aid dispersal in the springtime, an excellent time to catch mosses at work! But, since it is autumn and spring feels a long way off, you can experience more of Rhizomnium glabrescens on E-Flora BC and the Central Coast Biodiversity website.