Status: Native
Synonyms:
Barbula bolleana (Müll.Hal.) Brotherus
Barbula ehrenbergii (Lor.) Fleisch.
Meesia bolleana Müll.Hal.
Hydrogonium bolleanum is a perplexing rather robust moss that lives on rocks in streams in the open where it is partially
submerged most of the year. The stems are 3-5cm long. By habit, it looks like a densely tufted version of Schistidium rivulare. It can also be mistaken for Didymodon tophaceus. The leaves are very un-Pottiaceae in appearance. They commonly do not have papillae. The leaves are ovate to long lanceolate. The proximal cells are elongate. The distal cells are irregular to irregularly rectangular. The costa is strong and typically ends 3-5 cells before the apex. The apex in fresh and undamaged leaves is roundeded, usually obtuse but sometimes broadly acute. Perhaps the best clue to the ID in our specimens from New Mexico at least is the presence of a relatively high percentage of partially distally twinned leaves. Each stem typically has 2-4 leaves in which the costa splits at about a 20-30 degree angle and forms a partial secondary lamina usually more than halfway up the leaf. About 2-5% of leaves can be seen to partially twin in this manner in the dissecting scope. Microscopically, the cross section of the leaves is also rather distinctive with two strong stereid bands of granular cells. Twinning results in some rather interesting leaf cross sections. Normally, the costa is semicircular and has 4 guide cells. The costa becomes
wider, develops more guide cells, and eventually is cleft two form two costas. Interestingly, the each resulting costa must then develop the half of the lamina that it is missing. There is a differentiated epidermis that cover both the adaxial and abaxial surfaces.
Many thanks to John Brinda of the Missouri Botanical Garden for helping locate and ID this moss!
Please click on an image for a larger file.
Hydrogonium bolleanum, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, habit, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, habit, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, stems, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of "normal" leaf without twinning, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of cross section of leaf, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of cross section of leaf, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of distal laminar cells, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of leaf base, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of "normal" leaf apex, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of stem cross section, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of leaf with distal twinning, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of leaf with distal twinning, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of leaf with distal twinning, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of leaf with distal twinning, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of leaf with distal twinning, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of cross section of leaf with distal twinning, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of cross section of leaf with distal twinning, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of cross section of leaf with distal twinning, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
Hydrogonium bolleanum, photomicrograph of cross section of leaf with distal twinning, photo Russ Kleinman & Karen Blisard, Eddy County, Lincoln National Forest, Sitting Bull Falls, in creek near junction trail 217 with 68, May 22, 2020
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