Photo Tips for Shooting Bryaceae to ID.

@rolandwirth mentioned that he finds it helpful to know what to photograph for different groups of bryophytes in order to increase the likelihood of a species ID. I have made a posts about how to shoot liverworts for ID borne out of trying to ID other people's observations and wishing that photos might show particularly helpful features.

Any bryophyte observation is going to benefit from
(1) a habitat shot (showing substrate and associated bryophytes)
(2) a detailed habit shot of the bryophyte showing its general growth form (upright, scrambling, long leaves, hair points, distribution and form of sporophytes if present)
(3) a detail of the leaf
(4) a detail of the sporophyte (if possible).

While it is generally true that these small plants often need a microscope to make confident species IDs, some of them do have field characters that allow for a reasonably confident species ID from photographs. However, the characters required to photograph vary from group to group. In that spirit I thought I would try to write an overview of how to photograph various families of bryophytes by starting with the most tedious, nebulous, cursed and infuriating families of them all: Bryaceae. This group of mosses is one I come back to like a cryptic crossword, as if wanting to add irritation to my life. But it is also one of the most speciose groups in Western North America. If you are looking for a technical starting point, John Spence's somewhat informal Guide to the Identification of Bryaceae would be a good place to start, while his more technical treatment in Flora of North America is best for those armed with a microscope.

Here is what I have come to learn about accessible and useful photography over 5 years of trying to figure this family out.

(1) Asexual propagules. Look for little bud balls in the upper leaves (eg. Gemmabryum dichotomum, Bryum barnesii) or little red micropotatoes (eg. Bryum radiculosum) in the soil. The presence, shape, colour and number of these is a useful and photographable character,
(2) Leaf arrangement. Are the leaves evenly distributed and spaced along the stem (eg. Ptychostomum pseudotriquetrum) while others form rosettes (eg. Bryum capillaire) or grow in clusters along the stem (Bryum canariense)
(3) Leaf attachement-- Are the leave attached along a horizontal line or do they drape down the stem ("decurrent", as in Ptychostomum weigelii)
(4) Colour -- this is something that you can't help but catch. Things like Bryum miniatum and Bryum pallens can be rich shades of pink and red.
(5) Leaf apices -- hold the plant up to the sky so as to catch transmitted light through the leaf. Is the apex round? Is there a hairpoint (as in Bryum capillaire)? Is it made up of clear, non-photosynthetic cells (as in Bryum argenteum)?
(6) Leaf margin -- again hold up to the sky and let transmitted light through the leaf en route to your lens. Are there teeth? Does the margin have elongated cells? You can capture these at higher magnification or through a hand-lens+cell phone combo.
(7) Capsules- Honestly these are hit and miss, but if present you can try to photograph the # of sporophytes emerging from each shoot apex, as that varies within the family and sometimes within genera. The orientation of the capsules (whether pendulous or horizontal) can also be useful.

In the words of @johndreynolds "take the shot" if you a have it. If you have other things to add to this, throw it in the comments and I can try and update and incorporate.

Posted on January 25, 2024 03:26 AM by rambryum