Making sense of Syntrichia in the PNW

Syntrichia is one of the easiest moss genera to recognize. The broad leaves in a pinwheel arrangement, often with a red-orange hue around older growth, in combination with the prominent "awn" (a clear, discrete hairpoint at the end of the leaf) make it unmistakeable. If you are marginally lucky, the erect sporophytes with the elongate and twisted teeth are another feature that help define this group. After that, however, it gets a little hazy. Of the roughly 1000 iNaturalist observations of the genus in my immediate region (coastal SW BC & WA), about 60% of them purport to be Syntrichia ruralis, with S. princeps being the second-most observed species in the genus. These two are harder to distinguish that I thought. The problem is compounded by other very similar-looking taxa, like S. ruraliformis, S. papillosa and S. norvegica. This post attempts to seperate the species of Syntrichia based on hand-lens level features and habitat. Each linked species hereafter takes you to an iNaturalist observation that I think is representative. At the end of this post is a link to Syntrichia ID resources.

Syntrichia ruralis:

Habitat: This common species can be found epiphytic on hardwoods, concrete, mortar, limestone and limey soils from sea level to above the tree line. According to herbarium records, it is predominant species of arid regions.
Distinguishing characters: When wet, the leaves are squarrose-recurved, meaning they arch back to a 90 degree angle with the stem. The leaf margin is rolled over at the edges almost all the way to the apex of the leaf.
Advanced Characters: This species, unlike similair-looking S. princeps, has antheridia and archegonia on seperate plants ("dioicous"). To see this you can peel back the leaves around a developing sporophyte, place the base of the sporophyte in water on a slide and then squash it with a cover slip. Under the microscope, it will look like this if it only has archegonia, whereas it will look like this if it has both archegonia and antheridia.
One Line ID: leaves bent back to 90 degrees, margins rolled almost to the tip.
addendum: @terrymcintosh has chimed in below with his considerable experience and mentions that three other species are now verified as occuring in the coastal regions. All three of them are part of the Syntrichia ruralis complex treated in this A Scandinavian study and as best I can tell, a microscope would be needed to tease them apart. Syntrichia virescens is much like ruralis, but the leaf margins are plane in the distal half and under the microscope, the upper surface of the costa in cross section is covered by 1-2 rows of "stereid" cells (small, thick walled, tiny lumen), whereas in S. ruralis this is 3-6 rows thick. The other two species can be distinguished based on mamillae and papillae. Syntrichia papillosissma has tall bulging mamillae crowned by 1-2 papillae, whereas Syntrichia subpapapillosima, is TBD

Syntrichia princeps

Habitat: Concrete walls, mortar, cliffs crevices, sandy areas with mineral soil. Typically low elevation. Likes urban areas.
Distinguishing characters: These plants produce lots of sporophytes (reproduction is easier when every plant has the right parts). Schofield's guide notes that from the side, annual growth increments are visible as clusters of leaves along the stem. Unlike S. ruralis, S. princeps is supposed to have leaves that are constricted near mid-leaf. Even still I find this is a hard one to be sure of without a microscope.
Advanced Characters: A cross section through the leaf of S. princeps should show hyroids in the costa which is absent in S. ruralis and S. norvegica. Hydroids are wide-lumened water-conducting cells that are dead at maturity. I find these hard to recognize but you can look here for a iNaturalist discussion about it with links to good examples.
This species, unlike similair-looking S. ruralis, has antheridia and archegonia on the same plant in the same regions ("synoicous"). To see this you can peel back the leaves around a developing sporophyte, place the base of the sporophyte in water on a slide and then squash it with a cover slip. Under the microscope, it will look like this, with round antheridia mixed with occasional long-necked bottle-like archegonia. In S. ruralis, you will only find archegonia in these regions.
One Line ID: SYNOICOUS DISTURBOPHILE WITH CONSTRICTED MIDLEAF

Syntrichia norvegica

Habitat: Subalpine to Alpine on mineral soil and rocks.
Distinguishing characters: almost identical to S.ruralis, but with a red awn. Sometimes said awn can be green, in which case you'll need a microscope and some razors to distinguish it from S. ruralis. The leaves are purported to be "recurved" (rolled over at the edges) along most of the margin expect the distal 1/4 of the leaf, where the margin is plane/flat.
One line ID: RED AWN AT HIGH ELEVATION

Sytrichia laevipila

Habitat (in this region): Garry Oak Bark
Distinguishing characters: This is a tiny little Syntrichia with plane margins. It can be confused with small forms of S. princeps, but the margins on the latter are rolled back.
One line ID-TINY ON OAK WITH PLANE MARGINS

Syntrichia papillosa

Habitat: Epiphytic -- found once on a street tree in Vancouver
Distinguishing characters: This is going to look like standard Syntrichia except the margins are incurved (not rolled back or plane) and gemmae are purported to be present.
One Line ID: EPIPHYTIC WITH INCURVED MARGINS

Syntrichia latifolia

Habitat: Epiphytic on tree trunks (especially street trees in urban areas)
Distinguishing characters: The lack of a hairpoint, rounded leaf tips and medium size distinguish it from other species in the province. Some forms of S. laevipila lack the hair point, but these are much smaller. Under the microscope, S. latifolia a
One Line ID: MEDIUM-SIZED ROUND LEAVES NO HAIRPOINT ON TREES

Syntrichia ruraliformis

This species is not recognized in the Flora of North America treatment of Syntrichia, and all collections are synonymized with Syntrichia ruralis. In Europe, this taxon if variably recognized as a species, subspecies and variety. I mention it only because @michael-lueth pointed out an observation of similair form here on the eastern Vancouver Island
Habitat: Sand dunes, stony and rocky flats.
Distinguishing characters: Gradually tapering leaves that come to a point and end in the awn. The tips of the leafy section of the leaf tend to be clear (non-photosynthetic).
One Line ID: ACUMINATE SAND FORM WITH IMPOSTER SYNDROME AND HYALINE LEAF APICES

Links to Syntrichia Treatments

Flora of North America Treatment
California Moss eFlora Treatment
A Scandinavian study taking a multi-pronged but granular approach to teasing apart the very similar species of Syntrichia. Includes revised key and phylogeny but based on Scandinavian material.

Posted on Ιανουάριος 12, 2023 0743 ΜΜ by rambryum rambryum

Σχόλια

@stewartwechsler @bradenjudson @bstarzomski @terrymcintosh @david1945wagner @dbltucker @chlorophilia @cwardrop @fmcghee @astorey_botany if any of you have corrections, additions or comments on this I would appreciate any thoughts. I can incorporate them into an edited verion of this.

Αναρτήθηκε από rambryum περίπου 1 χρόνος πριν

Another great post! When are you going to write a book of one-line IDs?

Αναρτήθηκε από bradenjudson περίπου 1 χρόνος πριν

Excellent- very helpful @rambryum! I agree with @bradenjudson - love to see that book :)

Αναρτήθηκε από bstarzomski περίπου 1 χρόνος πριν

FYI, there are 12 accepted species for BC at the moment and about 5 more to come (based on European studies of our material; both newly described and older species). Hopefully, we will learn more this year. Three of our accepted species (S. papillosissima, S. subpapillosissima , and S. virescens) have been reported from coastal BC areas, with S. virescens being the most common.

Αναρτήθηκε από terrymcintosh περίπου 1 χρόνος πριν

Thanks again rambryum! Using the information in your post, and checking a couple more of my references, after largely not going beyond family on these, I've now dared to go to species on a few Syntrichia observations, that I have hopefully now gotten right!

Αναρτήθηκε από stewartwechsler περίπου 1 χρόνος πριν

terrymcintosh, I'd be interested in hearing what authority accepts those 12 species for BC, and indicates that S. virescens is the most common. I just checked e-FloraBC for S. virescens, and they say "There were no records found matching your search criteria". No doubt this might be the result of not keeping up with, or not agreeing with, some more recent taxonomy changes.

Αναρτήθηκε από stewartwechsler περίπου 1 χρόνος πριν

This is great!

From my experience with Ontario's Syntrichia norvegica, I find that this green is often blue-green; however, this character is probably variable. This observation https://inaturalist.ca/observations/93004503 shows this blue-green colour relatively well. Additionally, S. cainii appears to be the only Canadian Syntrichia not found in British Columbia. In case you are interested in making a Syntrichia of Canada post, here is some information on S. cainii. I hope to share more information on S. cainii sporophytes and ecology later this year.

Syntrichia cainii (edited)
Habitat: Calcareous rocks on Ontario alvars (Manitoulin Island to Napanee Plain). Often in moist locations with full to partial sunlight in large communities of mosses and algae.
Distinguishing Characteristics: Leaf margins revolute in proximal 1/2-3/4 of the leaf, similar to S. norvegica and S. ruralis. Leaves lack hair points and propagula.
Advanced Characteristics: Laminal cells collenchymatous
One line ID: SAXICOLOUS-CALCAREOUS ONTARIO. ALL LEAVES LACK HAIR POINTS.
Link to observations: https://inaturalist.ca/observations/141665353 https://inaturalist.ca/observations/141664103

Αναρτήθηκε από astorey_botany περίπου 1 χρόνος πριν

Response to Stewart. S. virescens is the most common of the three species on that list but still very rarely collected in BC (the S. ruralis complex is by far the most common 'species' across BC). So you know, e-Flora BC is a poor resource at best for bryophyte data as it is out of date. We (mainly Steve Joya and I) work out of the UBC Herbarium and have just finished a BC list of moss species...so, I suppose, it's our authority to a great degree but based on recent work by Dr. Kramer (in Germany but unpublished but we are hoping) and Dr. Gallego in Spain. Both taxonomists have or have had BC (and Washington) material of Syntrichia and are sorting it out with morphological and genetic work. But we must be patient as this takes time. Once completed (a year perhaps) I will provide a key 'known' Syntrichia species of the PNW. Alas, we must wait.

Αναρτήθηκε από terrymcintosh περίπου 1 χρόνος πριν

Response to Adam: I am originally from SW Ontario and helped Brent with his FNA treatment of Syntrichia so am familiar with S. cainii but have never seen it in the field. To me, the most distinguishing character are the collenchymatous laminal cells. Where are you based? BC is rich in all sorts of genera such as Syntrichia, but also Didymodon, the 'Racomitriums' (s.l.), etc. But we need a new BC moss flora! Lawton's excellent PNW flora is way out of date.

Αναρτήθηκε από terrymcintosh περίπου 1 χρόνος πριν

Thank you @terrymcintosh

Αναρτήθηκε από stewartwechsler περίπου 1 χρόνος πριν

Nice @rambryum! I would add that I more often see S. princeps as an epiphyte rather than on concrete. Also, when scouring concrete for Syntrichia, Tortula muralis is common. Not sure if you want to get into the Syntrichia/Tortula distinction here though.

Αναρτήθηκε από dbltucker περίπου 1 χρόνος πριν

@terrymcintosh I live in Severn, Ontario, about 5 km from the type location of Syntrichia cainii. In the field, it is distinct from S. ruralis and S. norvegica when hydrated. On alvars, S. cainii can be distinguished by the lack of hair points on all leaves and with recurved margins as mentioned above. It can be easy to spot in April to early June and September to November or after mid-summer rains, but it can be very challenging to find it in July-August if the conditions are dry. S. cainii can grow in monocultures (upto 1+ sq. m.), but more often with multiple species of Bryum, Ptychostomum, Tortella, Syntrichia, Schistidium, Thuidium, Brachythecium, Orthotrichum, and Climacium (very rarely) as well as a variety of cyanobacteria and other microorganisms (e.g., dinoflagellates). I don't have much experience with Didymodon, but I haven't found it with any S. cainii yet.

I haven't spent too much time looking for collenchymatous laminal cells because this species is the only Syntrichia in Ontario which lacks hair points on all of the leaves. I have edited my S. cainii comment to include collenchymatous laminal cells. Thank you bringing my attention to this character. My S. cainii specimens are at the Canadian Museum of Nature (Gatineau, Qc) at the moment, but I can take some better images of this character when I am there in February.

Αναρτήθηκε από astorey_botany περίπου 1 χρόνος πριν

This is wonderful folks- thanks for taking the time to write all this up. I'm afraid I am late to mosses and liverworts, and even later to collecting them for microscopy. I hope to do more of that this year, and am easing myself in. I really appreciate all the details here, and am also slowly learning the lingo, with my Malcolm at my side. Looking forward to that new PNW bryophytes flora :)

Αναρτήθηκε από bstarzomski περίπου 1 χρόνος πριν

To Adam: My daughter lives in Peterborough and nephew in Huntsville. I will be there sometime in spring possibly. Love to see S. cainii in the field. Alvars are really interesting for Schistidiums as well (you note them above). Have you collected many species?

Αναρτήθηκε από terrymcintosh περίπου 1 χρόνος πριν

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