Data mode


Sign up

Click the number at the start of a key lead to highlight both that lead and its corresponding lead. Click again to show only the two highlighted leads. Click a third time to return to the full key with the selected leads still highlighted.

Key to Eryngium

Copy permalink to share

1 Inflorescence unbranched, the heads solitary on peduncles from the leaf axils of the prostrate to erect stem.
  2 Leaves entire, irregularly toothed (rarely with some minor, irregular lobing).
    3 Heads subglobose or hemispherical when fully developed, about as wide as long; bracts subtending the head barely extending beyond the base of the head; main stems leaves linear, narrowly elliptic, narrowly oblanceolate, sometime tricuspid apically
    3 Heads cylindrical, longer than wide; bracts subtending the head longer than the radius of the head, thus extending conspicuously beyond the base of the head; main stem leaves elliptic, broader than above
1 Inflorescence branched, the heads in a cyme borne terminally on the erect or prostrate stem.
      4 Basal and cauline leaves unlobed (except sometimes the uppermost; note that bracts in the inflorescence are often lobed), 3-100 cm long; leaf margins without coarse spine-tips (finely spinulose in E. foetidum).
        5 Basal leaves evenly and rather finely toothed with spine-tipped teeth
        5 Basal leaves with entire or crenate margins, lacking spiny tips (though in some species with flexible bristles along the margins).
          6 Blades of basal and lower cauline leaves 3-7 (-10) cm long, acute to obtuse apically, cordate to truncate basally, with a length/width ratio of 1.5-3 (-6)
             7 Head hemispheric, about as wide as high; [native, seeps, bogs, and wet pine savannas, VA, KY, AR, and OK southwards]
             7 Head ovoid, taller then wide; [non-native from horticultural use]
          6 Blades of basal and lower cauline leaves 10-100 cm long, acuminate to acute apically, clasping basally, with a length/width ratio of 5-50.
               8 Leaves with primary veins pinnate-reticulate, with or without marginal bristles; flowers blue.
                 9 Styles 3.0-4.0 mm long at maturity, scarcely exceeding the bractlets (which subtend each flower); heads subglobose to hemispherical, 6-12 mm in diameter; middle cusp of the bractlets elongate, distinctly longer than the lateral cusps
                 9 Styles 4.0-6.0 mm long at maturity, exceeding the bractlets; heads globose, 9-15 mm in diameter; middle cusp of the bractlets about equal in length to the lateral cusps
               8 Leaves with primary veins parallel, with marginal bristles; flowers greenish-white.
                   10 Larger leaves < 1.5 cm wide; marginal bristles in fascicles of 1-3 (-4), those on the lower portion of the leaf usually in fascicles of 2-3
                   10 Larger leaves > 1.5 cm wide; marginal bristles of leaves solitary
                     11 Plant green; marginal bristles triangular (broadened at the base); flowering late
      4 Basal and cauline leaves (all, or at least many of the cauline) definitely deeply lobed into 3 or more divisions, < 10 cm long; leaf lobes tipped with moderately stiff to very stiff spine tips.
                            14 Heads 20-35 mm tall, purple to reddish; heads capped with conspicuous (1-2 cm long) spinescent bracts
                            14 Heads 4-15 mm tall, bluish to purplish; heads capped with a few, mostly entire, spinescent bracts, or lacking them.
                              15 Plants erect, stem solitary, branching upwards; fruits 1-2 mm long
                              15 Plants diffuse, decumbent, branched from the base and upwards; fruits 1.5-3 mm long
                          13 Heads greenish, whitish, or pale lavender; basal leaves pinnately or pinnately-ternately divided.
                                  17 Plants stout, fleshy, usually glaucescent; basal leaves 10-25 cm long and wide, pinnately or pinnate-ternately divided into > 7 segments, the cauline leaves similar but reduced in size and number of divisions; heads 10-15 mm in diameter; [rare ballast waif of disturbed ground]; [subgenus Eryngium]
                                  17 Plants slender, not fleshy, green; basal and cauline leaves 2-6 cm long, 3-5 (-7) pinnately parted; heads 5-8 mm in diameter; [native species of dry pinelands or scrub of the Coastal Plain of e. GA, s. AL, and FL].
                                    18 Basal leaves pinnately lobed; stems decumbent at base, ascending (the mature plant often wider than it is tall); stems leafy throughout their length, usually with 10 or more leaves; [dry pinelands and scrub of the Coastal Plain of e. GA, s. AL, and FL]
                                    18 Basal leaves trilobed; stems ascending at base (the mature plant taller than wide); stems erect, unbranched; stems sparsely leafy, especially upwards, usually with 7 or fewer leaves; [endemic in Florida scrub in Highlands County, c. peninsular FL]
Cite as...