User:Sesamehoneytart/Pteridophyte

Key to the true ferns and fern allies of Tennessee

Jump to Start

Key to the Pteridophytes

 * True Fern: Leaves usually foliaceous with branching veins. Sporangia on leaves or appendages of leaves (never in leaf axils, cones, or cavities at the base of leaves
 * Fern Ally: Leaves needle-like or scale-like with only a single midvein. Never foliaceous and young plants never have fiddleheads. Sporangia are in leaf axils, strobili, or cavities at the base of leaves.

Fern Ally

 * Isoetaceae: Heterosporous. No aerial stems. Leaves needle-like and arising from a corm. Sporangia in cavities near the base of leaves at or below ground level.
 * 2: aerial stems present, leaves absent, scale-like, or forming a sheath around the stem at nodes.

2

 * Equisetaceae: aerial stems hollow or fluted. Prominent joints unbranched or with nodal whorls of several branches. Strobili terminal.
 * 3: aerial stems not hollow or fluted. Leaves small, spiraled, scale-slike.

3

 * Selaginellaceae: Leaves with ligules. Spores in a flat or 4-sided strobilus. Heterosporous.
 * Lycopodiaceae: Leaves without ligules. Spores in leaf axils or in terminal strobili. Homosporous.

True Fern

 * 4: Plant aquatic or rooting where water usually would be if water levels are low.
 * 5: Plant terrestrial or rooting on rocks or trees.

4

 * Marsileaceae: Leaves needle-like or clover-like. Usually rooted in mud
 * Azolla caroliniana: Leaves with thalli, not clover-like. Stems floating.

5

 * 6: Leaves with thalli and usually less than a centimeter squared in total size
 * 7: Leaves much larger than a centimeter squared without thalli.

6

 * Hymenophyllaceae: Leaves with veins or filamentous strands. Spores in tubular indusia
 * Pteridaceae: Leaves without veins or spores. Usually have a fringe of filamentous projections.

7

 * Ophioglossaceae: Sporangia fused laterally into two rows on upright spikes or panicles on petiole above vegetative blade.
 * 8: Sporangia not fused.

8

 * 9: Fertile leaves appear to lack blade tissue
 * 10: Sporangia on margin or underside of flat parts, fertile parts green.

9

 * Osmundaceae: Leaves pinnate or more complex. Spores borne singly on axes of leaflets or pinnae.
 * Onoclea sensibilis: Leaves pinnatifid. Sporangia borne in clusters.

10

 * Lygodium palmatum: Leaves climbing by a vine-like midrib. Rhizome is terrestrial, hairy, and without scales.
 * 11: Leaves free-standing, not vine-like.

11

 * 12: Sori beneath the rolled up edge of leaflets.
 * 13: Sori without indusium or beneath a film or scale of tissue

12

 * Dennstaedtiaceae: Leaf blades generally over 30 centimeters long. Rhizome wide-creeping, hairy, and without scales.
 * Pteridaceae: Leaf blades generally over 30 centimeters long, clustered on a short, ascending, scaly rhizome.

13

 * 14: Long sori within a linear indusium
 * 15: Sori generally round, kidney-shaped, or densely gathered, covering the lower leaf surface.

14

 * Blechnaceae: Sori in one row on each side of leaf rib, lined end to end.
 * 16: Sori generally solitary and not end to end

15

 * Polypodiaceae: Blades pinnatifid
 * 17: Blades pinnate or more divided

16

 * Aspleniaceae: Glossy and wiry petiole with a deep red to black color.
 * Woodsiaceae: Petiole green to straw colored; not glossy or wiry.

17

 * Thelypteridaceae: Small, needle-like hairs present on rib, veins, and groove of petiole.
 * 18: No hairs present on rib, veins, or groove of petiole.

18

 * Woodsiaceae: Indusium pocket-like attached beside the sorus or ring of scale-like indusium portions aroud the edge of sorus.
 * Dryopteridaceae: Indusium kidney shaped or lepidote, rising above the sorus.

Aspleniaceae

 * ASP1: Leaves simple or pinnatifid. Leaves not pinnate.
 * ASP2: Leaves pinnatifid or more complex

ASP1

 * Asplenium rhizophyllum: Leaves rooting at the tips. Veins joined by cross-veins to form a network.
 * ASP3: Leaves not rooting at the tips. Veins free.

ASP2

 * ASP4: Leaves at most once pinnate.
 * ASP5: Leaves twice pinnate or more.

ASP3

 * Asplenium scolopendrium: Leaves simple, heart-shaped at the base, and linear to lanceolate.
 * Asplenium pinnatifidum: Leaves pinnatifid and triangular.

ASP4

 * Asplenium platyneuron: Leaflets alternate, nearly sessile, and with bases that overlap the midrib.
 * ASP6: Leaflets opposite and without petiolules

ASP5

 * Asplenium ruta-muraria: Plant with ovate to triangular leaves, green petioles, hairy indusia, and bluish living material
 * ASP7: Plant with dark petioles, entire indusia, and green living material

ASP6

 * Asplenium resiliens: Leaflets six to ten millimeters long, three to five times as long as wide, and generally widest at the base.
 * Asplenium trichomanes: Leaflets four to seven millimeters long, one to two times as long as wide, and generally widest above the base.

ASP7

 * Asplenium montanum: Leaf blades twice-pinnate throughout. Petiole all pale except at the base.
 * Asplenium bradleyi: Leaf blades twice pinnate only near base. Petiole dark reddish-brown.

Blechnaceae

 * Woodwardia areolata: Sterile leaves pinnate at the base, sometimes pinnatifid. Fertile leaves more erect and contracted.
 * Woodwardia virginica: Sterile and fertile leaves pinnate-pinnatifid throughout.

Dennstaedtiaceae

 * Pteridium aquilinum: Sori long to marginal, continuous beneath curled leaf edge. Leaves without hair or glands on stipes.
 * Dennstaedtia punctilobula: Sori round and discontinuous. Leaves with trichomes on stipes.

Dryopteridaceae

 * Polystichum acrostichoides: Spores covering entire lower surface of leaves where present. Indusia round and shield-like; with stalk attached to the lower surface.
 * Dryopteris: Spores never covering entire lower surface of leaves. Indusia are kidney-shaped and attached within the sinus of the kidney-shaped sorus.

Dryopteris

 * DRY1: Leaves pinnate-pinnatifid to twice pinnate at the base
 * DRY2: Leaves are twice pinnate to three times pinnate-pinnatifid at the base

DRY1

 * Dryopteris marginalis: Petioles have a dense tuft of tawny scales at the base. The sori are at or near the leaf edges.
 * DRY3: Petioles have tan to dark brown scales at the base. Sori not on the leaf edges.

DRY2

 * Dryopteris intermedia: Leaves more or less evergreen with the previous year's leaves usually next to leaves of current year. Glands on stipes present on rachis and leaflet midribs.
 * DRY4: Leaves deciduous. No glands on stipes present.

DRY3

 * Dryopteris cristata: Fertile leaves erect and linear to lanceolate. Fertile leaves two to three times as long as vegetative leaves.
 * DRY5: Basal leaflets ovate. Petiolar scales dark brown or with a dark brown stripe.

DRY4

 * Dryopteris carthusiana: Indusium without hair. Leaves are ovate to lanceolate.
 * Dryopteris campyloptera: Indusium occasionally with glands. Leaves are ovate to triangular.

DRY5

 * Dryopteris goldiana: Sori are closer to the midvein than the leaflet edge. Leaves narrow abruptly near the top.
 * Dryopteris celsa: Sori are halfway between the midvein and leaflet edge. Leaves gradually narrow near the top.

Equisetaceae

 * Equisetum arvense: Fertile stem unbranched and without chlorophyll. Sterile stems have many circular arrangements of secondary branches.
 * Equisetum hyemale: Fertile and sterile stems similar and usually unbranched or with few branches.

Hymenophyllaceae

 * Hymenophyllum tayloriae: Thalloid gametophyte ribbon-like, irregular, and branched, usually fringed with very small finger-like projections.
 * Trichomanes: Sporophytes between thalloid and typical fern habit with bristles on margins or a single row of filamentous gametophytes

Trichomanes

 * Trichomanes intricatum: Uniseriate filamentous gametophyte
 * TRI1: Thalloid or fern-like sporophytic plants

TRI1

 * Trichomanes boschianum: Leaves pinnately lobed to compound.
 * Trichomanes petersii: Leaves more or less thalloid and leaflets entire to slightly lobed.

Isoetaceae

 * ISO1: Aquatic plants
 * ISO2: Terrestrial plants, though sometimes found in shallow waters, especially during rainy seasons.

ISO1

 * Isoetes valida: A curtain-like membrane covers more than half of spores.
 * ISO3: A curtain-like membrane covers less than a quarter of spores.

ISO2

 * Isoetes melanopoda: Leaves black near the base.
 * Isoetes butleri: Leaves greenish-brown near the base.

ISO3

 * Isoetes appalachiana: A curtain-like membrane covers 20 to 25 percent of sporangia.
 * ISO4: A curtain-like membrane covers 10 to 20 percent of sporangia.

ISO4

 * Isoetes engelmannii: Megaspores are 380 to 508 micrometers in diameter.
 * Isoetes tennesseensis: Megaspores are 616 to 946 micrometers in diameter.

Lycopodiaceae

 * Huperzia: Fertile leaves similar to sterile leaves
 * LYC2: Fertile leaves broader, shorter, or more spreading than sterile leaves.

LYC2

 * Lycopodiella: Plants in wet soils. Rhizome dies back annually.
 * LYC3: Plants in dry soils. Rhizome persistent and trailing.

LYC3

 * LYC4: Erect leafy stems are over a centimeter in diameter.
 * LYC5: Erect leafy stems are 2 to 8 millimeters in diameter.

LYC4

 * Spinulum annotinum: One strobilus per erect stem. Strobili are sessile.
 * Lycopodium clavatum: One to six strobili per erect stem. Strobili on peduncles.

LYC5

 * Diphasiastrum: Strobili are on long narrow peduncles. Leaves are scale-like and appressed to the stem. Leafy branches are usually less than 3 millimeters wide.
 * Dendrolycopodium: Strobili are sessile. Leaves are awl-shaped. Leafy branches are usually five to eight millimeters wide.

Dendrolycopodium

 * Dendrolycopodium obscurum: Leaves are unequal in size. Upright stems flat.
 * LYCden1: Leaves equal in size. Upright stems round.

LYCden1

 * Dendrolycopodium hickeyi: Leaves dark green, appressed, and not prickly.
 * Dendrolycopodium dendroideum: Leaves are pale green, spreading, and prickly.

Diphasiastrum

 * Diphasiastrum digitatum: Terminal fronds flat in cross-section and usually green.
 * Diphasiastrum tristachyum: Terminal fronds square in cross-section and bluish

Huperzia

 * Huperzia lucidula: Leaves narrowly obovate and one to eight toothed.
 * LYChup1: Leaves lanceolate or oblanceolate. Leaves are entire or with one to three short teeth.

LYChup1

 * Huperzia appressa: Leaf margins entire or with occasional papillae. Usually found at high elevations in igneous substrates.
 * Huperzia porophila: Leaf margins few papillae or large teeth. Usually found at mid to low elevations in sandstone.

Lycopodiella

 * Lycopodiella appressa: Erect stems are less than 4 millimeters in diameter. Leaves of peduncle and strobilus appressed and entire.
 * Lycopodiella alopecuroides: Erect stems over 6 millimeters in diameter. Leaves of peduncle incurved an those of the strobilus are spreading with ciliate margins.

Marsileaceae

 * Pilularia americana: Leaves thread-like and lack expanded blade tissue
 * Marsilea minuta: Palmately divided leaves with long petioles, appearing clover-like

Ophioglossaceae

 * Ophioglossum: Leaves entire; never dissected or lobed.
 * OPH1: Leaves clearly dissected

OPH1

 * Sceptridium: Common petiole of sterile and fertile leaf portions terminating near the ground.
 * OPH2: Common petiole of sterile and fertile leaf portions rising well above the ground.

OPH2

 * Botrypus virginianus: Sterile blade broadly triangular, ternate to 2 or 3 pinnate, and herbaceous
 * Botrychium: Sterile blade narrowly triangular or elliptic, pinnatifid to pinnate, and fleshy-herbaceous

Botrychium

 * Botrychium simplex: Sterile leaves nearly simple to pinnatifid
 * Botrychium matricariifolium: Sterile leaves once to twice pinnate

Ophioglossum

 * Ophioglossum crotalophoroides: Sterile portion of blade lying on the ground, triangular to heart-shaped
 * OPHoph1: Sterile portion of blade erect to spreading, ovate to lanceolate

OPHoph1

 * Ophioglossum engelmannii: Veins of leaf blade forming small areoles within larger areoles. Usually in calcium rich soil.
 * Ophioglossum pycnostichum: Veins of leaf blade not different in size or prominence. Usually in neutral soil.

Sceptridium

 * Sceptridium jenmanii: Lower leaflets long-petiolulate and clearly alternate
 * OPHsce1: Lower leaflets short-petiolulate and opposite to subopposite

OPHsce1

 * Sceptridium oneidense: Terminal segments of sterile blade ovate, obovate, or rhombic with blunt or rounded apex.
 * OPHsce2: Terminal segments of sterile blade lanceolate to lance-ovate with an acute apex.

OPHsce2

 * Sceptridium biternatum: Sterile blades mostly twice pinnate.
 * Sceptridium dissectum: Sterile blades mostly three times pinnate.

Osmundaceae

 * Osmundastrum cinnamomea: Fertile leaves with monomorphic pinnae
 * Osmunda: Fertile leaves with dimorphic pinnae

Osmunda

 * Osmunda claytoniana: Leaves pinnate-pinnatifid. Fertile pinnae in the middle of the blade.
 * Osmunda regalis: Leaves twice pinnate. Fertile pinnae at the terminal end of the blade.

Polypodiaceae

 * Pleopeltis polypodioides: Blades with numerous peltate scales on underside of leaf
 * Polypodium: Blades either lacking peltate scales or only associated with midrib.

Polypodium

 * Polypodium appalachianum: Leaf blade widest at base. Leaf tips narrowly rounded to acute. Stem scales are golden brown
 * Polypodium virginianum: Leaf blade widest in the middle. Leaf tips rounded to obtuse. Stem scales are dark brown.

Pteridaceae

 * Vittaria appalachiana: Plants thalloid; leaf area less than 1 centimeter squared
 * PTE1: Plants not thalloid; leaf area much larger than one centimeter squared.

PTE1

 * Adiantum: Sori round or oblong; sori distinct along leaf edge.
 * PTE2: Sori continuous along leaf edge.

PTE2

 * Pellaea: Leaves without hair or with very little hair. Leaf edges strongly reflexed. Terminal segments over eight millimeters long.
 * Cheilanthes: Leaves hairy. Margins recurved. Terminal segments one to four millimeters long.

Adiantum

 * Adiantum capillus-veneris: Leaves pinnate
 * Adiantum pedatum: Leaves dichotomously branching like a fan

Cheilanthes

 * Cheilanthes alabamensis: Leaf segments without hair or with very few hairs
 * PTEche1: Leaf segments covered with villae or downy hairs

PTEche1

 * Cheilanthes tomentosa: Leaves three times pinnate. Stipe and rachis have flattened white scales.
 * Cheilanthes lanosa: Leaves twice or three times pinnate. Stipe and rachis have hair, but don't have scales.

Pellaea

 * Pellaea atropurpurea: Petiole and rachis dull and sparsely or not hairy.
 * Pellaea glabella: Petiole and rachis shiny and hairy.

Selaginellaceae

 * Selaginella rupestris: Leaves in spirals with obvious bristle-tips
 * Selaginella apoda: Leaves four-ranked, but not in spirals or bristle tipped.

Thelypteridaceae

 * Phegopteris: Leaves bipinnatifid, less than twice as long as wide. Rachis with adnate pinnae wings. Sori without indusia
 * THE1: Leaves pinnately dissected and easily twice as long as wide. Rachis without adnate pinnae wings. Sori with indusia

THE1

 * Thelypteris: Leaves pinnate to pinnate-pinnatifid. Costae with an adaxial groove.
 * Macrothelypteris torresiana: Leaves twice to three times pinnate. Costae lacking an adaxial groove.

Phegopteris

 * Phegopteris hexagonoptera: Rachis has a continuous wing between the two basal pairs of pinnae. Leaves are about as long as wide.
 * Phegopteris connectilis: Rachis wing is interrupted between the two basal pairs of pinnae. Leaves are about twice as long as wide.

Thelypteris

 * Thelypteris noveboracensis: Medial pinnae over four times longer than basal most pinnae
 * THEthe1: Medial pinnae about equal in length to basal pinnae

THEthe1

 * Thelypteris simulata: Underside of leaves have resin glands. Costae lack scales. Lateral veins of pinnae lobes are not forked.
 * Thelypteris palustris: Underside of leaves do not have glands, but have tan scales. Lateral veins of pinnae lobes are branching.

Woodsiaceae

 * WOO1: Sori are round
 * WOO2: Sori are elongate

WOO1

 * Woodsia: Indusium is cuplike, composed of scale-like or filamentous segments
 * Cystopteris: Indusium is hoodlike, arching over the sorus. It is attached to the lamina on one side only.

WOO2

 * Athyrium filix-femina: Sori is crescent or J-shaped. Leaves are twice or three times pinnate.
 * WOO3: Sori is straight or slightly curved. Leaves are pinnate to pinnate-pinnatifid.

WOO3

 * Deparia acrostichoides: Midrib is silvery and hairy. Leaves are pinnate-pinnatifid.
 * Diplazium pycnocarpon: Midrib is without hair. Leaves are pinnate.

Cystopteris

 * WOOcys1: Rachises and costae have glandular hairs. Leaves are widest at or near the base.
 * WOOcys2: Rachises and costae do not have glandular hairs. Leaves are widest near the middle.

WOOcys1

 * Cystopteris bulbifera: Rachises and costae densely covered with glandular hairs.
 * Cystopteris tennesseensis: Rachises and costae sparsely covered with glandular hairs.

WOOcys2

 * Cystopteris protrusa: Stem hairy.
 * Cystopteris tenuis: Stem without hair.

Woodsia

 * Woodsia appalachiana: Leaflets have whitish scales. Mature petioles are reddish brown to dark purple.
 * Woodsia obtusa: Leaflets are without scales. Mature petioles are light brown to yellow.