Lindsaea

Rojas-Alvarado, Alexander Francisco & Tejero-Díez, José Daniel, 2017, Novelties and notes in Lindsaea (Lindsaeaceae) from Mexico and Central America, Phytotaxa 296 (2), pp. 147-160 : 157-158

Key to Mexican and Central American species of Lindsaea

1. Acroscopic margins of segments undulate and with some short clefts; sori irregularly interrupted, at least in the more developed segments.............................................................................................................................................................................................2

- Acroscopic margins of segments entire or repand; sori typically continuous....................................................................................4

2. Blades 2-pinnate (Neotropics).................................................................................................................................................... L. feei

- Blades 1-pinnate.................................................................................................................................................................................3

3. Blades lanceolate with 5–15 pinnae pairs, pinnae 3–6 times longer than wide, subequilateral, with primary vein centered; spores trilete ( Costa Rica, Panama, Greater Antilles, South America) ........................................................................................ L. imrayana

- Blades linear-elliptic, with 30–50 pinnae pairs, pinnae as long as wide, dimidiate, with primary vein sympodial basiscopic; spores monolete ( Panama, Colombia) ........................................................................................................................................ L. seemannii

4. Sori present along both sides of segments (acroscopic and basiscopic); segments long-triangular, at least 5 times longer than wide; first vein dimidiate at base and centered at the apex ( Costa Rica, Panamá, Ecuador) ....................................................... L. taeniata

- Sori present only along acroscopic side of segments; segments triangular to rectangular or similar, less than 4 times as long as wide; first vein full dimidiate.............................................................................................................................................................5

5. Longer segments less than 2-times longer than wide.........................................................................................................................6

- Longer segments more than 2-times longer than wide.....................................................................................................................10

6. The largest blades or longest pinnae with 35–75 segment pairs; if blade with two basal pinnae then these held vertically.............7

- The largest blade or pinnae with less than 30 segments pairs; if 2-pinnate, the pinnae not held vertically.......................................8

7. Blades 1 or 2-pinnate; segments rectangular with acroscopic side convex; spores trilete (Neotropical) ............................. L. stricta

- Blades 1-pinnate; segments triangular with acroscopic sides concave; spores monolete ( Costa Rica, Panama) ............. L. pratensis

8. Stipes (at least distally) and rachises dark brown to grayish..................................................................................... L. fuscopetiolata

- Stipes (at less distally) and rachises stramineous (yellowish to green-yellow) or with dark shadows..............................................9

9. Blades 1-pinnate (or sometimes 2-pinnate at the base); basal segments distant (> 1 cm apart) and ascending; fronds 5–20 cm long ( Nicaragua, Cuba) ............................................................................................................................................................... L. cubensis

- Blade fully 2-pinnate (to 3-pinnate in base); basal segments close (– 0.9 cm), and perpendicular or descending (reflexed); fronds (15–) 25–70 cm long (Neotropics) ................................................................................................................................. L. moritziana

10. Distal segments (of blades or pinnae) only weakly reduced at least 75 % the size of proximal segments), apical segments subconform (0.8–2.0 cm broad at base); rachises angular abaxially, sometimes winged...........................................................................11

- Distal segments strongly reduced less than 75% the size of proximal segments, apical segments reduced to less than 0.7 cm broad; rachises terete abaxially, never winged............................................................................................................................................14

11. Stipes (at least distally) and rachises stramineous (yellowish to green-yellow); blades fully 2-pinnate (Neotropics) ......... L. lancea

- Stipes (full) and rachises (at least proximally in L. angustipinna ) atropurpureous to brawn or blackish; blades 1- pinnate, or basally 2-pinnate...........................................................................................................................................................................................12

12. Basiscopic side of segments straight and commonly perpendicular to rachis, the apex curved up to truncate; laminar tissue pale green; indusia brown ( Nicaragua, Costa Rica) ............................................................................................................ L. angustipinna

- Basiscopic side of segments curved down, the apex acute; laminar tissue dark green (blackish when dry); indusia stramineous ...............................................................................................................................................................................................................13

13. Fronds 10–25 cm long in adult plants; blade 1-pinnate, with 10-17 (-22) pinnae pairs ( Costa Rica, South America).... L. leprieurii

- Fronds 40–50 cm long in adult plants; blade 1 or more commonly 2-pinnate, if 1-pinnate then with more than 25 pinnae pairs ( Mexico to Costa Rica)........................................................................................................................................... L. mesoamericana

14. Stipes and rachises (at least proximally) brown to blackish; blades 2-pinnate................................................................................15

- Stipes (at least distally) and rachises stramineous (yellowish to green-yellow; blades 1 or 2-pinnate............................................16

15. Pinnae short-petiolulate, with a deltate acroscopic subaxillar segment, lateral segments broader at the base than the apex ( Mexico, Mesoamerica, Greater Antilles, N. South America) ........................................................................................................... L. subalata

- Pinnae long-petiolulate, without an acroscopic subaxilary segment; lateral segments as broad at base than the apex ( Guatemala, Costa Rica, Panama, South America) .............................................................................................................................. L. divaricata

16. Blades 1-pinnate (or 2-pinnate at the base); segments triangular with acute apices ( Costa Rica, Panama, northern South America) ...................................................................................................................................................................................... L. horizontalis

- Blades fully 2-pinnate; segments trapezoidal-rectangular with rounded to truncate apices (Neotropical) ......................... L. arcuata