By Daniel K. Palmer and Paul Wilson
Department of Biology, California State University, Northridge, CA 91330-8303
paul.wilson@csun.edu
Work with Grimmia requires cross-sections made near the middle of a leaf. These cross-sections must be thin enough to turn over on their sides so that the anatomy of that section can be seen. Past work with Grimmia has emphasized the presence or absence of hyaline awns but those features are not completely reliable — almost any normally awned species can be found without awns. A plant can be said to have an hyaline awn even when only a few terminal cells on the leaf are hyaline. In a cross-section, the guide cells have large lumens and thin walls much like the cells of the lamina and they are positioned along the adaxial surface. Sometimes other cells that are inward of the guide cells also have larger lumens than the sterid cells of the costa (insert labeled diagram).
How Grimmioideae differs from Racomitrioideae
A. Alar region with numerous quadrate cells; capsule always immersed; mostly found in wet habitats.....Schistidium A' In most species alar region poorly differentiated with proximal cells of leaf rectangular; capsules mostly emergent; usually in dry habitats......B
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| Schistidium occidentale alar region with quadrate cells (Shevock 22601) | Grimmia nevadensis alar region with rectangular cells (Norris 106467) |
B. Except for a short mucron, leaf apex obtuse or nearly so, never awned .....Hygrogrimmia mollis B' Leaf tip awned or at least sharply acute on at least distal most leaves .....C
C. Leaf cross-section at 400× showing hourglass-shaped vertical walls with the cells deeper than wide and with elliptical lumina; calyptra large and mitrate to campanulate, plicate......Cocinodon C' Laminal cells in cross-section with cell walls following the ± angular shape of lumin; calpytra as above (in Jauffalobryum) or not (in Grimmia) .....D
D. Leaf lamina unistratose throughout and margins not differentiated; hyaline awn on at least some of the leaves extending farther down the costa than down the margins; calyptra campanulate or if mitrate large, plicate; perichaetial leaves larger than the adjacent vegetative leaves .....Jauffalobryum D' Leaf lamina bistratose or unistratose with a bistatose margins, sometimes with bistratose streaks; leaf tip not hyaline or if hyaline awn arising from truncate apex of green or somewhat decurrent down the leaf margins; calyptra cucullate or if mitrate not much larger than operculum, not plicate; perichaetial leaves often not as above ......Grimmia
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| Jauffalobryum raui cross section showing unistratose leaves (Norris 18390) | Grimmia lisae cross section showing bistratose leaves (Sagar 365) |
A. Leaf distinclty keeled, best seen in cross section .....Jauffalobryum raui A' Leaf not keeled in cross section .....Jauffalobryum wrightii
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| Jauffalobryum raui distincly keeled leaf (Norris 18390) | Jaffalobryum wrightii leaf not distincly keeled (Shevock 16526) |
A. Leaf lamina ± unistratose (except for margin and a few distal streaks), best seen in cross-section; capsules in most species wrinkled longitudinally ..... B A' Leaf lamina bistratose or thicker in cross-section, at least in distal half; capsules in most species smooth ..... D
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| Grimmia trichophylla cross section showing unistratose leaves (Colman 818) | Grimmia caespiticia cross section showing bistratose leaves (Shevock 24475) |
B. Leaves broadly ovate-oblong, never awned with costa failing to reach leaf apex, with unistratose laminae; cells of lamina more than 10 µm broad .....Hygrogrimmia mollis B' Leaf shape various (many species ± lanceolate), many species awned at least the parachaetial leaves, costa often excurrent, most species with multistratose margins; cells of lamina less than 10 um broad .....C
C. Leaves keeled to weakly concave; leaf margins usually recurved at least on one side; leaf usually lanceoloate; capsules usually wrinkled longitudinally .....Rhabdogrimmia C' Leaves broadly concave; leaf margins usually plane; leaf oblong-ovate to oblong-lanceolate; seta attached off-center to side of base of capsule; capsules usually smooth .....Gastrogrimmia2
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| Grimmia lisae leaf keeled (Sagar 365) | Grimmia plagiopoda laef broadly concave (Norris 55864) |
D. Leaves keeled, i.e., adaxial surface shaped like a } in cross-section though not necessarily with a sharp point ......Guembelia D' Leaves concave, i.e., adaxial surface smoothly shaped like a ) in cross-section or with costa bulging adaxially .....E
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| Grimmia caespiticia leaf keeled (Shevock 24475) | Grimmia leavigata laef broadly concave (Palmer 71) |
E. Dioicous; seta attached to center of base of capsule; capsules exserted in most species; proximal leaf lamina hyaline or not ......Litoneuron E' Dioicous or gonioautoicous; seta attached off-center to side of base of capsule; capsule immersed; proximal lamina ± hyaline .....Gastrogrimmia2
A. Gemmae almost always present on leaf tips or abaxially on leaves toward apex of shoot .....B A' Gemmae rarely present, or if present, then in leaf axils .....C
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| Grimmia anomola gemmae on leaf tip (Norris 105718) | Grimmia leigerbii gemmae absent (Norris 106976) |
B. Gemmae on leaf tips; leaves not particularly contorted when dry .....G. anomola B' Gemmae on abaxial surface of leaves; leaves strongly contorted when dry ......G. torquata
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| Grimmia anomola gemmae on leaf tip (Norris 105718) | Grimmia torquata gemmae on leaf (Coleman 637) |
C. Awn absent; cross section at mid leaf with strong logitudinal ridges on abaxial surface ......Grimmia ramondii C' Leaves with obvious hyaline awn or small mucron .....D
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| Grimmia ramondii awn absent (Norris 105718) | Grimmia leigerbii awn present (Norris 106976) |
D. Transition between hyaline awn and green lamina ± shaped like an upside down U with hyaline tissue decurrent down margins (lamina ignoring hyaline tissue rounded distally); in all species, awns at least of fertile leaves about as long as green lamina; gonioautoicous; plants generally in discrete clumps; leaves except for awn not particularly acuminate, usually shorter than 2.5:1, ......E D' Transition between hyaline tissue and green lamina ± truncate with hyaline tissue not extending down margins; in some species, leaf tips with only a very small faction of leaf hyaline or even mucronate; dioicous; plants often spreading indefinitely into carpets; leaves with a long acumen, lanceolate, usually much longer than 2.5:1 .....G
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| Grimmia pulvinata broad leaf tip distinct from awn (Sagar 134) | Grimmia lisae narrow leaf tip indistinct from awn (Sagar 485) |
E. Hyaline awn present only on perichaetial leaves with vegetative leaves bluntly rounded; basal juxtacostal cells with straight lateral wall; operculum conical to mammalate .....Grimmia moxleyi E' Both perichaetial and vegetative leaves with a hyaline awn; walls of basal juxtacostal cells nodulose; operclum various .....F
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| Grimmia moxleyi perichaetial leaf on left with awn, vegitative leaf on right with no awn (Wilson 4334) | Grimmia lisae all leaves with a distinct awn (Sagar 485) |
F. Proximal laminal cells variably quadrate and short-rectanular; operculum rostrate; perigonium located in a leaf axil a few leaves below the perichaetium; calyptra mitrate, covering little more than the operculum; peristome teeth mostly entire .....Grimmia pulvinata F' Proximal laminal cells uniformly short or long-rectanular; operculum mammalate; perigonia terminal on branch stems; calyptra cucullate; peristome teeth cribrose, often irregularly split; .....Grimmia orbicularis
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| Grimmia pulvinata proximal veiw of leaf showing non-uniform basal cels (Sagar 134) | Grimmia orbicularis proximal veiw of leaf showing uniform basal cells (Shevock 19025) |
G. Leaf margins incurved; leaf tips contorted when dry ......Grimmia incurva G' Leaf margins recurved; leaves scarcely contorted when dry or straight ......H
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| Grimmia incurva plant with incurved margins when dry (Norris 74684) | Grimmia pulvinata plant with margins not incurved (Newell 250) |
H. Costa in cross-section at mid-leaf with ridges running abaxially and longitudinally .....Grimmia muhlenbeckii H' Costa in cross-section at mid-leaf rounded .....I
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| Grimmia muhlenbeckii cross section with ridge on abaxial side of costa (Norris 83098) | Grimmia trichophylla cross section showing rounded abaxial side of costa (Coleman 818) |
I. Costal guide cells fewer than 4 at mid leaf, one or a few cells inward of guide cells also usually with larger lumens than sterids; basal cells long retangular; leaf insertion usually about 30 degrees and arch of leaf less than a half circle; leaf tissue often aging to reddish-brown ......Grimmia trichophylla I' Costal guide cells 4 or more at mid leaf, cells below guide cells all with very small lumens; basal cells short or long; leaf insertion and arch of leaf various; leaf tissue aging without any tent of red ......J.
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| Grimmia trichophylla cross section showing two guide cells and sub guide cells (Colman 818) | Grimmia lisae cross section showing four guide cells (Sagar 365) |
J. Basal cells thick-walled and sinuous, long rectangular (almost all >3:1); the rest of the lamina tending to be sinuose also; leaf insertion usually about 30 degrees and arch of leaf less than a half circle; said to have a central strand (though poor sectioning disguises it); leaf tissue aging to the color of motor oil (brownish olive) .....Grimmia leibergii
J' Basal cells scarcely sinuouse, short rectangular (many <2:1); mid-leaf cells a bit sinuous, distal laminal cells not noticably sinuose; leaf insertion when wet often much more than 30 degrees and arch of leaf more than 180 degrees (giving the macroscopic impression of pin-wheels); central strand lacking; leaf tissue aging toward black .....Grimmia lisae
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| Grimmia leibergii basal cells long reqtangular with strongly sinuose cells (Shevock 28926) | Grimmia lisae basal cells short reqtangular with mostly straight cells (Sagar 365) |
A. Hyaline awns lacking or at least not prominent ..... B
A' Hyaline awns very prominent ..... D
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| Grimmia hamulosa no awn present (Wilson 5132) | Grimmia torenii prominent awn (Toren 9355) |
B. Leaf tip generally obtuse from oblong-lanceolate leaves, sometimes with a small mucron .....Grimmia unicolor [questionably present in California, a lake shore species if we had good material, it would be important to compare to G. brevirostris to find other characters besides the lack of hyaline leaf tips in G. unicolor]
B'. Leaf tip acute; leaves slightly to strongly falcate; small hyline awns sometimes present .....C
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| Grimmia unicolor rounded leaf tip (JMH) | Grimmia hamulosa acute leaf tip (Wilson 5132) |
C. Leaves falcate-secund; shoots long; seta longer .....Grimmia hamulosa
C' Leaves with a shorter acumen, not so secund; shoots shorter; seta shorter .....Grimmia brevirostris [sometimes lumped with G. hamulosa]
D. Costa decurrent; costa at base about ten cells wide in abaxial view; costa not at all grooved adaxially in distal portion of leaf; basal cells except for a few juxtacostal ones not at all elongate; alar cells numerous, mostly transversely elongate .....Grimmia laevigata
D' Costa not decurrent, variously restricted to an adaxial channel but never so flattened; basal and alar cells not transversely elongate ..... E
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| Grimmia leavigata strongly decurrent awn (Palmer 51) | Grimmia torenii non decurrent awn (Toren 9355) |
E. Margins greatly thickened (multistatose and with interior cells thick-walled like the stereids in the costa); in addition to the costa and margins, multistratose leaf bands present in leaf lamina .....Grimmia serrana
E' Margins scarcely thicker than lamina (bistratose); leaf lamina uniformly bistratose between costa and margins ..... F
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| Grimmia serrana costa like leaf margins (Toren) | Grimmia torenii leaf bistratose throughout (Norris 106467) |
F. Basal laminal cells short-rectangular (2:1), mostly uniform from costa to margin, thin-walled; peristome absent; capsules short and wide (widest nearly at mouth); proximal laminal cells of uniform length from margin to costa with straight thin walls .....Grimmia nevadensis F' Basal laminal cells long-retangular (3_:1) or greater, basal cells nearest costa long-reqtangular becomming short-reqtangular near margins, thick-walled; peristome present; capsule length:width 2:1 or longer; proximal marginal cells short and contrasting with long juxtacostal cells with sinuose thick walls .....G
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| Grimmia nevadensis short basal cells (Norris 106467) | Grimmia ovalis long basal cells (Shevock 18549) |
G. Distal laminal cells smooth; perichaetial leaves not particularly differentiated from slightly smaller vegetative leaves; awn smooth or somewhat denticulate; capsules exserted with seta 4-5 mm long; peristome teeth solid and separate; habit loose, branched; often on acidic (granitic) or neutral rocks or decomposed rocks .....G. ovalis
G' Distal laminal cells mammalate-pappilose; perichaetial leaves inflated and filmy-hyaline except near the chlorophyllose apex; awn strongly denticulate; capsules immersed; peristome teeth disarticulated and sometimes fused at base; habit not branched in tight turfts; on basic sandstone or pillow basalt .....G. torenii
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| Grimmia ovalis mostly smooth awn (Shevock 18549) | Grimmia torenii highly denticulate awn (Toren 9355) |
A. Leaf lamina ± unistratose (except for margin and a few distal streaks), best seen in cross-section .....B A' Leaf lamina bistratose or thicker in cross-section, at least in distal half .....C
B. Peristome lacking; leaf margins bistratose, lamina with occastional bistratose streaks; abaxial surface V-shaped; basal laminal cells long-rectangular (sometimes more than 2:1) .....G. anodon B' Peristome well developed; leaf margins 1-2-stratose, lamina uniformly unistratose; abaxial surface concave; basal laminal cells quadrate to short-rectangular (less than 2:1) .....G. plagiopoda
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| Grimmia anodon leaf with bistratose margins and bistratose streaks (Palmer) | Grimmia plagiopoda leaf margin one stratose (Norris 55864) |
C (no specimens for this couplet) Gonioautoicous; leaf cell walls thick (thicker than other Grimmia); peristome well developed ......G. americana C' Dioicous; leaf cell walls thin (like other Grimmia); peristome rudimentary ......G. crinitoleucophacea
A. Gemmae abundant at the distal end of the leaf .....Grimmia shastae A. Gemmae absent ..... B
B. (no specimen) Costa in cross-section circular with an arch adaxially between the laminae; hyaline awn short (0.3 mm), decurrent .....Grimmia teretinervis B' Costa in cross-section semicircular with the two laminae forming a V adaxially; hylaine awn various ..... C
C Distal portion of leaf bistratose with unistatose streaks ..... D C' Distal portion of leaf uniformly bistratose ...... E
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| Grimmia reflexidens bistratose leaves with unistratose streaks (Norris 106955) | Grimmia caespiticia uniformly bistratose leaves (Shevock 24475) |
D. Awn short; basal juxtacostal cells rectangular and thin walled .....Grimmia sessitana D' Awn generally long 1-3 mm; basal cells rectangular and thick walled ..... Grimmia reflexidans
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| comming soon | Grimmia reflexidens leaf with long awn (Norris 106955) |
E. Leaves sometimes bulging best seen by cross section .....F. E' Leaves never bulging .....
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| Grimmia alpestris cross section showing bulging leaf cells (Lo B15) | Grimmia montana cross section showing no bulging leaf cells (Shevock 19383) |
F. Distal margins plane or incurved ..... G F' Margins recurved, at least on one side ..... J
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| Grimmia montana margin incurved (Shevock 19383) | Grimmia longirostris cross section showing margin recurved (Shevock 29499) |
G Leaf margins plane; cells not bulging .....G. donniana G' Leaf margins incurved distally; cells sometimes bulging ...... H
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| comming soon | Grimmia mariniana leaf with incuved margins (Toren 8601) |
H. (key step needs work) Medial leaf cells sinuose, not bulging .....G. mariniana H'. Medial leaf cells not sinuose .....I
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| comming soon | comming soon |
I. Leaf cells that are sometimes bulding; basal cells and medial cells quadrate to short rectangular .....G. alpestris
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| Grimmia ovalis awn short (Shevock 18549) | Grimmia montana basal cells short rectangular (Norris 105062) |
J. Costa in cross-section semicircular; leaf bases sheathing; capsule immersed; dioicous ......G. arizonae J' Costa in cross-section reniform; leaves not sheathing; capsule emergent to exserted; cladautoicous ......G. longirostris
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| no specimen () | Grimmia longirostris costa in cross section reniform (Shevock 29499) |