Orthotrichum pumilum
“low bristle moss”
![Orthotrichum pumilum photo by Bob Klips](https://ohiomosslichen.org/wp-content/uploads/2013/12/Orthotrichum-pumilum-7-466x700.jpg)
Orthotrichum pumilum on masonry in Columbus, Ohio.
April 20, 2011.
![Orthotrichum pumilum photo by Bob Klips](https://ohiomosslichen.org/wp-content/uploads/2013/12/Orthotrichum-pumilum-2-700x466.jpg)
Orthotrichum pumilum on masonry in Columbus, Ohio. January 23, 2012.
![Orthotrichum pumilum photo by Bob Klips](https://ohiomosslichen.org/wp-content/uploads/2013/12/Orthotrichum-pumilum-9-700x466.jpg)
Orthotrichum pumilum (leaves without brood bodies) with Syntrichia papillosa. March 7, 2013.
How to recognize low bristle moss: Orthotrichum pumilum occurs in small dark green tufts. It is a cushion moss with little 1-1.5 mm long capsules barely emergent above the upper leaves. This moss genus has significant differences between the capsules which require a compound microscope to sort them out. The calyptra (capsule cover while developing) is naked or sometimes with a few sparse hairs. The apiculate leaves which are erect when dry and wide spreading when wet, have large cells compared to other species in this genus (14-20 microns long); this and technical features of the sporophyte (immersed stomata; distinctively 8-ribbed capsules) distinguish this from several similar species.
Where to find low bristle moss: Orthotrichum pumilum occurs on the bark of hardwoods and masonry, commonly along roadsides in cities.