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 distal lamina is bistratose. 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. We initially found it in the Carson National Forest and those pix are here.
Please click on an image for a larger file.



Rhexophyllum subnigrum, habit, photo Russ Kleinman & Karen Blisard, Grant County, Gila National Forest, Little Cherry Creek Ranch Road, November 21, 2021



Rhexophyllum subnigrum (dry), photo Russ Kleinman & Karen Blisard, Grant County, Gila National Forest, Little Cherry Creek Ranch Road, October 25, 2021



Rhexophyllum subnigrum, wettened stems, photo Russ Kleinman & Karen Blisard, Grant County, Gila National Forest, Little Cherry Creek Ranch Road, October 25, 2021



Rhexophyllum subnigrum, photomicrograph of single stem, photo Russ Kleinman & Karen Blisard, Grant County, Gila National Forest, Little Cherry Creek Ranch Road, October 25, 2021



Rhexophyllum subnigrum, photomicrograph of single leaf, photo Russ Kleinman & Karen Blisard, Grant County, Gila National Forest, Little Cherry Creek Ranch Road, October 25, 2021



Rhexophyllum subnigrum, photomicrograph of leaf apex, photo Russ Kleinman & Karen Blisard, Grant County, Gila National Forest, Little Cherry Creek Ranch Road, October 25, 2021



Rhexophyllum subnigrum, photomicrograph of stem cross section with central strand, photo Russ Kleinman & Karen Blisard, Grant County, Gila National Forest, Little Cherry Creek Ranch Road, October 25, 2021



Rhexophyllum subnigrum, photomicrograph of distal leaf cross section (bistratose), photo Russ Kleinman & Karen Blisard, Grant County, Gila National Forest, Little Cherry Creek Ranch Road, October 25, 2021



Rhexophyllum subnigrum, photomicrograph of distal leaf cross section (bistratose), photo Russ Kleinman & Karen Blisard, Grant County, Gila National Forest, Little Cherry Creek Ranch Road, October 25, 2021



Rhexophyllum subnigrum, photomicrograph of distal leaf cross section (bistratose), photo Russ Kleinman & Karen Blisard, Grant County, Gila National Forest, Little Cherry Creek Ranch Road, October 25, 2021



Rhexophyllum subnigrum, photomicrograph of midlaminal cells, photo Russ Kleinman & Karen Blisard, Grant County, Gila National Forest, Little Cherry Creek Ranch Road, November 21, 2021


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