Selaginella

Smith, Alan R. & Kessler, Michael, 2018, Prodromus of a fern flora for Bolivia. III. Selaginellaceae, Phytotaxa 344 (3), pp. 248-258 : 249-251

Key to the Bolivian species of Selaginella

1 Leaves of branches and stems ± uniform, spirally arranged ............................................................................................................ 2

– Leaves of branches and often the main stems dimorphic, disposed in 4 ranks with 2 smaller upper ranks and 2 larger lateral ranks ........................................................................................................................................................................................................... 3

2 Leafy stems ± dorsiventral, with larger leaves on the adaxial side; bases of the lower leaves (and often upper leaves) strongly decurrent on the stems; dried stems upturned ............................................................................................................... S. peruviana

– Leafy stems radially symmetric; leaf bases abruptly adnate (rarely decurrent on main stems); dried stems straight ...... S. sellowii

3 Stems with articulations at the nodes, with a sunken, often darkened ring at or just below each of the often swollen nodes; rhizophores usually arising on the adaxial side of the stems, opposite the axillary leaves .............................................................. 4

– Stems lacking articulations at the nodes; rhizophores usually arising on the lower side of the stems .......................................... 10

4 Stems pubescent; plants scandent, scrambling over other vegetation, mostly 2–8 m long .............................................. S. exaltata

– Stems glabrous; plants erect to prostrate, usually less than 1 m long .............................................................................................. 5

5 Main stems unbranched at the bases, erect; leaves monomorphic on unbranched part of stems .................................... S. asperula

– Main stems branched from the bases, prostrate to ascending; leaves dimorphic throughout, the lateral ones on the main stems spreading ........................................................................................................................................................................................... 6

6 Axillary leaves with two long (to 0.5 mm), ± straight, narrow, basal auricles whose tips are sometimes inwardly or outwardly curved ................................................................................................................................................................................. S. sulcata

– Axillary leaves not auriculate, or auricles smaller, their tips not usually curved ............................................................................. 7

7 Axillary leaves not auriculate or only faintly so, with ciliate bases, the hairs often 2-celled ............................................ S. diffusa

– Axillary leaves with entire bases ...................................................................................................................................................... 8

8 Median leaves basally peltate, apically acuminate; median and lateral leaves narrowly white-margined .................. S. marginata

– Median leaves basally each with one auricle, apically aristate; median and lateral leaves with greenish margins ......................... 9

9 Median leaves oblanceolate, long-aristate; lateral leaves 4–7 mm long; stems with one vascular bundle ..................... S. silvestris

– Median leaves ovate, short-aristate; lateral leaves 6–9 mm long; stems with two vascular bundles ............................. S. trisulcata

10 Stems tufted, rosette-like, curling inward when dry ...................................................................................................... S. convoluta

– Stems not tufted, not curling when dry .......................................................................................................................................... 11

11 Plants with distinct, erect main stems, the leaves on stems below lowermost branches ± uniform and appressed ....................... 12

– Plants creeping or erect, if erect, then lateral leaves on main stems spreading (except sometimes at the stem base) ................... 15

12 Main stems stramineous or greenish .................................................................................................................................. S. anceps

– Main stems reddish or brownish ..................................................................................................................................................... 13

13 Main stems toward bases dark brown, completely hidden by strongly overlapping leaves; oldest leaves on main stems with pronounced, wide, brown borders ................................................................................................................................. S. convoluta

– Main stems toward bases reddish, visible between adjacent leaves (not strongly overlapping); oldest leaves on main stems with greenish, or slightly reddish, narrow borders ................................................................................................................................. 14

14 Lateral leaves basally ciliate to ciliolate acroscopically; plants 10–30 cm tall ............................................................ S. erythropus

– Lateral leaves minutely denticulate to entire; plants 30–65 cm tall ........................................................................... S. haematodes

15 Rhizophores emerging throughout main stems and on branches ................................................................................................... 16

– Rhizophores restricted to the bases of the main stems ................................................................................................................... 22

16 Median leaves short-cuspidate, the tips up to 1/6 times the leaf length ......................................................................................... 17

– Median leaves long-aristate, the tips 1/3–1 times the leaf length ................................................................................................... 18

17 Lateral leaves acute; leaves grayish green; semideciduous Chiquitano forests on sandstone .................................... S. cabrerensis

– Lateral leaves obtuse; leaves adaxially dark bluish-green, abaxially with a dull whitish cast; humid Andean foothill forests .......... .......................................................................................................................................................................................... S. truncata

18 Lateral leaves ciliate at bases ......................................................................................................................................................... 19

– Lateral leaves entire to denticulate at bases ................................................................................................................................... 20

19 Median leaves long-ciliate; margins of lateral leaves flat; adaxial surfaces of lateral leaves glabrous ......................... S. alampeta

– Median leaves denticulate; margins of lateral leaves revolute; adaxial surfaces of lateral leaves with minute hairs (30 × magnification needed) ............................................................................................................................................................................. S. revoluta

20 Lateral leaves on main stems 0.5–2.5 mm long ............................................................................................................ S. calosticha

– Lateral leaves on main stems 3–4.5 mm long ................................................................................................................................ 21

21 Median leaves aristate, the tips 1/2 –1 times the leaf length ........................................................................................... S. flexuosa

– Median leaves acuminate, the tips to 1/4 times the leaf length ....................................................................................... S. producta

22 Lateral leaves on main stems 7–10 mm long, 3–5 times as long as wide .................................................................. S. chrysoleuca

– Lateral leaves on main stems 0.2–5 mm long, 1–3 times as long as wide ..................................................................................... 23

23 Lateral leaves on main stems 0.2–0.5 mm long, tightly clasping the stems ............................................................... S. microphylla

– Lateral leaves on main stems 1–5 mm long, loosely arranged to spreading .................................................................................. 24

24 Lateral leaves on main stems 4–5 mm long, 2.5–4 times as long as wide; main stems 1–3 mm thick ....................... S. haenkeana

– Lateral leaves on main stems 1–3.5 mm long, 1–3 times as long as wide; main stems 0.2–1 mm thick ....................................... 25

25 Acroscopic margin of lateral leaves ciliate at bases ....................................................................................................................... 26

– Acroscopic margin of lateral leaves entire to denticulate at bases ................................................................................................. 28

26 Median leaves of branches aristate .................................................................................................................... S. novae-hollandiae

– Median leaves of branches acuminate ............................................................................................................................................ 27

27 Stems erect; median leaves orbicular at stem bases, apices obtuse and ciliate ............................................................ S. leucoloma

– Stems creeping-ascending; median leaves ovate at stem bases, apices acute ................................................................... S. minima

28 Median leaves long-aristate, tips>1/3 times the leaf length .......................................................................................................... 29

– Median leaves acute to short-aristate, tips <1/3 times the leaf length ............................................................................................ 30

29 Lateral leaves oblong; median leaves narrowly elliptic; margins of lateral and medial leaves, especially the latter, conspicuously hyaline ........................................................................................................................................................................ S. chionoloma

– Lateral and median leaves broadly ovate; margins of lateral and medial leaves green or very narrowly hyaline ......... S. flagellata

30 Median leaves obovate .............................................................................................................................................. S. glossophylla

– Median leaves elliptic to ovate ....................................................................................................................................................... 31

31 Lateral leaves with numerous, small hairs on the adaxial surfaces (30 × magnification needed) .......................... S. popayanensis

– Lateral leaves glabrous or nearly so ............................................................................................................................................... 32

32 Plants 0.5–5 cm tall; apices of lateral microphylls acute to acuminate; dorsal microphylls long-acuminate to aristate; sporophyll margins greenish, serrate to serrulate; semihumid habitats, to 1200 m ............................................................................. S. simplex

– Plants 4–22 cm tall; apices of lateral microphylls acute; dorsal microphylls acuminate; sporophyll margins whitish, denticulate to short-ciliate; humid montane habitats, 1100–3400 m .................................................................................................................... 33

33 Lateral leaves 2.5–3.5 mm long; median leaves broadly ovate .................................................................................... S. moritziana

– Lateral leaves 1–2.5 mm long; median leaves narrowly lanceolate to narrowly ovate .................................................................. 34

34 Median leaves narrowly lanceolate, gradually tapering into ill-defined tips ............................................................. S. angustifolia

– Median leaves narrowly ovate, rather abruptly reduced and acuminate at tips .............................................................................. 35

35 Lateral leaves lacking hyaline borders; dorsal sporophylls strongly acuminate ............................................................ S. bryophila

– Lateral leaves with hyaline borders; dorsal sporophylls acute ....................................................................................................... 36

36 Median leaves about 2/3 the length of the lateral leaves; lateral leaves obtuse to broadly acute, acroscopically serrate to serrulate; stem apices frequently flagelliform; strobili 2–6 mm long ............................................................................................. S. cavifolia

– Median leaves about 1/2 the length of the lateral leaves; lateral leaves acute, acroscopically ciliate; stem apices not flagelliform; strobili 1.5–2.5 mm long ............................................................................................................................................... S. solomonii