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A Perspective Oriented Guide for the Identification of North American Moss Genera
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| Home | Abbreviated Overview | Geographical Abbreviations | Concordance |
Overview
Revised through 30 June 2010
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Initial Groups ("naked-eye" characters) |
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Plants essentially leafless, consisting of strongly inclined, highly asymmetric capsules on stout papillose seta; the "bug-on-a-stick" mosses; WS * |
Buxbaumia |
| Plants scattered on a bed of abundant, persistent protonemata; plants & leaves small to minute. | Group A Sub-Guide | Skeleton |
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Plants small to minute (mostly <5 mm high) with ±immersed capsules growing on bare soil, usually as winter annuals; the "pygmy ephemerals" as defined here. |
Group B Sub Guide | Skeleton |
| Plants rosulate (leaves in a tight rosette at stem apex) and large (diameter 1-2 cm); WS | Rhodobryum |
| Plants erect with clusters of branches (fascicles) along the stem & at the apex (capitulum); WS | Sphagnum† |
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† In part, i.e., not all of the species within this genus will key to this Group. The other species will key to an appropriate Group. |
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| Plants from an erect, unbranched stipe, and either dendroid (tree-like) or frondose (fern-like).# | Group C Sub-Guide | Skeleton |
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# Note - the several mostly prostrate "fern-mosses" lacking a stipe are NOT included here, but will be found in the pleurocarpous Groups below. |
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| Plants with pendulous branches hanging loosely from tree branches. | Group D Sub-Guide | Skeleton |
| Plants projecting horizontally from vertical surfaces or with upturned/curled branch tips. | Group E Sub-Guide | Skeleton |
| Plants growing on dung, decaying animal matter, or other highly nitrogenous materials; the "dung mosses". | Group F Sub-Guide | Skeleton |
| Plants lacking any of the above unique “growth forms”; Continued below at left margin. | |
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Plants freely branched, i.e., with leafy stems & branches; usually prostrate in wefts or mats. |
Groups P1 on |
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Plants rarely branched, i.e., lacking obvious branching; usually erect in tufts, cushions or turfs. |
Groups A1 on |
Freely Branched (mostly pleurocarpous) Mosses |
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Plant Characters Section (naked eye) |
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| Plants strongly flattened (complanate) or angular. | Group P1 Sub-Guide | Skeleton |
| Plants julaceous both wet & dry (shoots round; leaves crowded, overlapping, and appressed).# | Group P2 Sub-Guide | Skeleton |
| Leaves spreading at right angles (squarrose) or squarrose-recurved; leaf tips often channeled. | Group P3 Sub-Guide | Skeleton |
| Plants with erect branches from a creeping stem. | Group P4 Sub-Guide | Skeleton |
| Plants with leaves sickle-shaped and turned to one side (falcate-secund). | Group P5 Sub-Guide | Skeleton |
| Plants or leaves lacking any of the above unique characters; Continued below at left margin. | |
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# Note - many other taxa have leaves crowded & appressed when dry, but spreading when wet. |
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Leaf and Stem Characters Section (hand lens) |
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| Plants with paraphyllia or tomentum on stems. | Group P6 Sub-Guide | Skeleton |
| Plants with red stems. | Group P7 Sub-Guide | Skeleton |
| Plants appearing “braided” (shoots flat on top & bilaterally symmetric; leaves falcate-secund). | Group P8 Sub-Guide | Skeleton |
| Leaves undulate or rugose (irregular undulations). | Group P9 Sub-Guide | Skeleton |
| Leaves dimorphic (2 different forms [size and/or shape] on the same axis).# | Group P10 Sub-Guide | Skeleton |
| Leaves with awns or hair points. | Group P11 Sub-Guide | Skeleton |
| Plants thread-like (stems little branched; leaves <1 mm). | Group P12 Sub-Guide | Skeleton |
| Plants or leaves lacking any of the above unique characters; Continued below at left margin. | |
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# Note - many other taxa have stem leaves differing from branch leaves. |
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Costa Characters Section (dissecting scope) |
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| Costa double & more than 1/3 leaf length. | Group P13 Sub-Guide | Skeleton |
| Costa single & narrow. | |
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Leaves with distinct decurrencies. |
Group P14 Sub-Guide | Skeleton |
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Leaves with a distinct marginal border. |
Group P15 Sub-Guide | Skeleton |
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Leaves with distinct alar cells. |
Group P16 Sub-Guide | Skeleton |
| Costa short & double, or none. | |
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Leaves with distinct decurrencies. |
Group P17 Sub-Guide | Skeleton |
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Leaves with a distinct marginal border. |
Group P18 Sub-Guide | Skeleton |
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Leaves with distinct alar cells. |
Group P19 Sub-Guide | Skeleton |
| Costa of uncommon or variable form (Y-shaped; forked; with lateral spurs or supplementary costae) | Group P20 Sub-Guide | Skeleton |
| Costa neither double & long, nor of an uncommon form; leaves lacking any of the above unique characters; Continued below at left margin. | |
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Reminder - Definitions for cell length to breadth ratios are found in the Introduction, the Overview & at the end of this section. |
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Leaf Cell Ratio Section (compound microscope) |
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| Leaf cells long (>8:1). | |
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Cells distinctly papillose or prorulose. |
Group P21 Sub-Guide | Skeleton |
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Cells smooth or indistinctly ornamented.# |
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Costa single. |
Group P22 Sub-Guide | Skeleton |
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Costa double (long or short), or none. |
Group P23 Sub-Guide | Skeleton |
| Leaf cells intermediate (3-8:1). | |
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Cells distinctly papillose or prorulose. |
Group P24 Sub-Guide | Skeleton |
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Cells smooth or indistinctly ornamented.# |
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Costa single (narrow or wide). |
Group P25 Sub-Guide | Skeleton |
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Costa double (long or short), or none. |
Group P26 Sub-Guide | Skeleton |
| Leaf cells short (<3:1). | |
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Cells distinctly papillose or prorulose. |
Group P27 Sub-Guide | Skeleton |
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Cells smooth or indistinctly ornamented.# |
Group P28 Sub-Guide | Skeleton |
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# Note - cells indistinctly papillose, i.e., low papillae or projections. An expanded explanation of the difference between "Distinct" and "Indistinct" surface ornamentation is found in the Introduction. |
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Cells = medial, laminal cells; cells ~2/3 of the way from insertion to apex, midway between the costa & the margin. Cell length to breadth ratio:
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Rarely Branched (mostly acrocarpous) Mosses |
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"Naked-eye" Characters |
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| Shoots flattened or angular (2-5 ranked) in cross-section, i.e., not round. | Group A1 Sub-Guide | Skeleton |
| Shoots julaceous both wet and dry (catkin-like; leaves crowded, overlapping and appressed).# | Group A2 Sub-Guide | Skeleton |
| Stems tomentose (densely covered by rhizoidal tomentum to near the apex). | Group A3 Sub-Guide | Skeleton |
| Stems red. | Group A4 Sub-Guide | Skeleton |
| Leaves squarrose-recurved (spreading at right angles with down-turned tips; shoots brush-like). | Group A5 Sub-Guide | Skeleton |
| Leaves falcate-secund (sickle-shaped & turned to one side; shoots broom-like). | Group A6 Sub-Guide | Skeleton |
| Leaves subulate-setaceous (awl, bristle, or needle-like; length to breadth 8:1 or greater). | Group A7 Sub-Guide | Skeleton |
| Shoots, stems or leaves lacking any of the above unique characters; Continued below at left margin. | |
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# Note - many species have leaves crowded and appressed when dry, but spreading when wet. |
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"Hand-lens" Characters |
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| Leaves finger-like and irregularly inserted; NW. | Takakia |
| Leaves dimorphic (2 different forms [size and/or shape] on the same axis). | Group A8 Sub-Guide | Skeleton |
| Leaves with a distinct hyaline hair-point or awn on vegetative leaves.# | Group A9 Sub-Guide | Skeleton |
| Leaves with lamellae, ridges, or filaments on their laminae or costae. | Group A10 Sub-Guide | Skeleton |
| Leaves undulate (distinct transverse waves or ridges). | Group A11 Sub-Guide | Skeleton |
| Leaves involute (margins distinctly incurved, inrolled, spirally inrolled or inflexed). | Group A12 Sub-Guide | Skeleton |
| Leaves lacking any of the above unique characters; Continued below at left margin. | |
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# Note - some species have these hair-points only on the upper leaves; species with hair-point son perichaetial leaves only will be found in other Groups. |
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"Dissecting microscope" Characters |
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| Leaves +all costa, lacking laminae; multistratose. | Group A13 Sub-Guide | Skeleton |
| Leaves with a broad, single costa (>1/3 the leaf width). | Group A14 Sub-Guide | Skeleton |
| Leaves with a narrow, single costa. | |
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Leaves with bases distinctly incurved to expanded & sheathing. |
Group A15 Sub-Guide | Skeleton |
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Leaves with long, pronounced decurrencies. |
Group A16 Sub-Guide | Skeleton |
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Leaves with a defined group of hyaline cells that stand in distinct contrast to densely papillose or chlorophyllose cells |
Group A17 Sub-Guide | Skeleton |
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Leaves with distinct marginal border of differentiated cells (ciliate; cells long, short, pale, hyaline, or thick-walled) |
Group A18 Sub-Guide | Skeleton |
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Leaves with distinctly differentiated alar cells (cells enlarged, inflated, quadrate, thick-walled, or colored) |
Group A19 Sub-Guide | Skeleton |
| Leaves with costae extremely reduced to lacking. | Group A20 Sub-Guide | Skeleton |
| Leaves lacking any of the above unique characters; Continued below at left margin. | |
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Reminder - Definitions for cell length to breadth ratios are found in the Introduction, the Overview & at the end of this section. |
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"Compound microscope" Characters |
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| Leaf cells long (>5:1). | |
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Cells smooth. |
Group A21 Sub-Guide | Skeleton |
| Leaf cells intermediate in length (2-5:1). | |
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Cells distinctly papillose. |
Group A22 Sub-Guide | Skeleton |
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Cells distinctly prorulose. |
Group A23 Sub-Guide | Skeleton |
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Cells smooth or indistinctly ornamented.# |
GroupA24 Sub-Guide | Skeleton |
| Leaf cells short (<2:1). | |
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Cells distinctly papillose. |
Group A25 Sub-Guide | Skeleton |
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Cells smooth or indistinctly ornamented.# |
Group A26 Sub-Guide | Skeleton |
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# Note - cells bulging, mammillose (both bulging and papillose) or indistinctly papillose, i.e., low papillae. An expanded explanation of the difference between "Distinct" and "Indistinct" surface ornamentation is found in the Introduction. |
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Cells = medial, laminal cells; cells ~2/3 of the way from insertion to apex, midway between the costa and the margin. Cell length to breadth ratio:
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| Home | Abbreviated Overview | Geographical Abbreviations | Concordance |