Plants of the Gila Wilderness

Presented in Association with the
Western New Mexico University Department of Natural Sciences

Rhexophyllum subnigrum (Mitten) Thériot ex Hilpert

Family: Pottiaceae

Status: Native

Synonyms:
Neocardotia subnigra (Mitt.) Thér. & E.B. Bartram

Rhexophyllum subnigrum has lanceolate leaves that are strongly keeled at the apex where coarse, multicellular teeth can be found on leaves that have not been heavily eroded. The cells are multipapillose. The costa has 4 guide cells and two stereid bands. The overall impression is that it is very similar to Leptodontium flexifolium. R. subnigrum has a reddish cast, while L. flexifolium is yellowish green. The best objective character to separate the two taxa is the presence of a stem central strand in Rhexophyllum subnigrum, and the absence of a central strand in Leptodontium flexifolium. L. flexifolium is usually found on bark, while Rhexophyllum subnigrumis most commonly found on rocks. We found Rhexophyllum subnigrum at middle to upper elevation in mixed conifer forest.
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Rhexophyllum subnigrum (dry), photo Russ Kleinman & Karen Blisard, San Miguel County, Porvenir Canyon, May 6, 2019



Rhexophyllum subnigrum, wettened stems, photo Russ Kleinman & Karen Blisard, San Miguel County, Porvenir Canyon, May 6, 2019



Rhexophyllum subnigrum, photomicrograph of leaf, photo Russ Kleinman & Karen Blisard, San Miguel County, Porvenir Canyon, May 6, 2019



Rhexophyllum subnigrum, photomicrograph of leaf, photo Russ Kleinman & Karen Blisard, San Miguel County, Porvenir Canyon, May 6, 2019



Rhexophyllum subnigrum, photomicrograph of leaf, photo Russ Kleinman & Karen Blisard, San Miguel County, Porvenir Canyon, May 6, 2019



Rhexophyllum subnigrum, photomicrograph of leaf apex, photo Russ Kleinman & Karen Blisard, San Miguel County, Porvenir Canyon, May 6, 2019



Rhexophyllum subnigrum, photomicrograph of leaf base, photo Russ Kleinman & Karen Blisard, San Miguel County, Porvenir Canyon, May 6, 2019



Rhexophyllum subnigrum, photomicrograph of multicellular teeth at margin of leaf, photo Russ Kleinman & Karen Blisard, San Miguel County, Porvenir Canyon, May 6, 2019



Rhexophyllum subnigrum, photomicrograph of cross section of stem with central strand, photo Russ Kleinman & Karen Blisard, San Miguel County, Porvenir Canyon, May 6, 2019



Rhexophyllum subnigrum, photomicrograph of cross section of leaf with mostly bistratose lamina, photo Russ Kleinman & Karen Blisard, San Miguel County, Porvenir Canyon, May 6, 2019



Rhexophyllum subnigrum, photomicrograph of cross section of leaf with mostly unistratose lamina, photo Russ Kleinman & Karen Blisard, San Miguel County, Porvenir Canyon, May 6, 2019



Rhexophyllum subnigrum, photomicrograph of cross section of leaf with regions that are bistratose, photo Russ Kleinman & Karen Blisard, San Miguel County, Porvenir Canyon, May 6, 2019


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