Key to Polystichum

View taxon page for Polystichum

(For a list of species in Polystichum, use the above link.)

Jepson Manual glossary definitions can be seen by moving your cursor over words underlined with dots.

1. Leaf generally 1-pinnate, rarely to partly 2-pinnate; pinnae generally 

simple 

Composed of a single part; undivided; unbranched.

, ± 

entire 

Having margins that are continuous and smooth (i.e., without teeth, lobes, etc.).

to 

serrate 

Having margins with sharp, fine to coarse teeth generally pointing tipward, not outward; margins with such teeth on such primary teeth are doubly serrate.

, in Polystichum kruckebergii sometimes 1-lobed

2. Leaf 10–15(25) cm; pinnae simple or generally lobed at bases of lowest ..... P. kruckebergii (2)

2' Leaf 10–120(200) cm; pinnae simple

3. Proximal pinnae ± 

deltate 

More or less equilaterally triangular, with the corners rounded or not.

, ± 1/2 longest; stipe 1/10–1/6 

blade 

Expanded portion of a leaf, petal, or other structure, generally flat but sometimes rolled, cylindric, wavy, or cupped.

..... P. lonchitis

3' Proximal pinnae 

ovate 

Egg-shaped (i.e., widest below the middle) in two dimensions (i.e., in one plane), as a leaf.

to 

lanceolate 

Narrowly elongate, widest in the basal half, often tapered to an acute tip.

, ± = to ± 2/3 longest; stipe generally 1/5–1/2 blade

4. Stipe base scales ovate, ± 3(6) mm wide, those above proximal pinnae generally > 1 mm wide, persistent; pinnae generally in 1 plane; 

indusium 

In many ferns, a veil- or scale-like outgrowth of the leaf surface that covers a sorus.

 

ciliate 

Having generally straight, conspicuous hairs along margins or edges.

..... P. munitum

4' Stipe base scales lanceolate, ± 2–3 mm wide, those above proximal pinnae generally < 1 mm wide, falling early; pinnae ± in 1 plane or not; indusium ± entire to toothed ..... P. imbricans

5. Leaf 15–80 cm; pinnae ± in 1 plane, longest 3–6(10) cm; sori submarginal ..... subsp. curtum

5' Leaf 15–50 cm; pinnae often not ± in 1 plane, longest 2–5 cm; sori ± near midvein ..... subsp. imbricans

1' Leaf 1–2-pinnate, rarely to partly 3-pinnate; pinnae deeply pinnately lobed to 1-pinnate, at least at bases of lowest

6. Segment teeth without bristle-like tips; serpentine ..... P. lemmonii

6' Segment teeth with bristle-like tips; serpentine or not

7. Leaf generally 2- to rarely partly 3-pinnate; pinnules abruptly narrowed to attachment < 0.5 mm wide, often with a 

lobe 

1. A major expansion or bulge, such as on the margin of a leaf, sepal, or petal, or on the surface of an ovary. 2. The free tips of otherwise fused structures, such as sepals or petals; larger than teeth.

on distal side of base; 

rachis 

In ferns, primary axis of a compound or dissected frond blade.

with persistent scales ..... P. dudleyi

7' Leaf generally 1- to partly 2-pinnate; pinnules gradually 

tapered 

Gradually (not abruptly) narrower or smaller at base or tip.

to attachment < 3 mm wide, 

lobes 

1. A major expansion or bulge, such as on the margin of a leaf, sepal, or petal, or on the surface of an ovary. 2. The free tips of otherwise fused structures, such as sepals or petals; larger than teeth.

0; rachis with deciduous scales

8. Smallest scales on abaxial blade surface hair-like; blade generally > 5 cm wide ..... P. californicum

8' Smallest scales on abaxial blade surface 

linear 

Elongate, with nearly parallel sides; narrower than elliptic or oblong.

, few hair-like; blade generally < 5 cm wide

9. Proximal pinnae ± deltate, longest < 1(1.5) cm ..... P. kruckebergii (2)

9' Proximal pinnae ± lanceolate, longest 1.5–3 cm ..... P. scopulinum

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