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Key to Yucca

Agavaceae

Yucca

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(c) Cressler, Alan M.
(c) Campos, Aidan
1 Plants caulescent when fully developed (an erect shrub or small tree), the lower parts of the stem readily visible because no longer clothed with leaves.
(c) Hardin, J.W.
(c) Sorrie, Bruce A. - CC-BY
  2 Leaf margins regularly fraying from the leaf as stiff threads; leaves 3-5 cm wide; fruits pendent berries with soft flesh, 7-14 cm long; [e. TX and westwards]
  2 Leaf margins not fraying from the leaf as stiff threads; leaves 2.5-8 cm wide; fruits pendent or erect berries with leathery or soft flesh, 2.5-11.5 cm long; [collectively widespread, from se. VA south to s. FL, west to s. AZ].
    3 Fruits with soft flesh, 5-11.5 cm long; leaves very stiff; leaf surface dull; leaves persistent only on upper trunk; [c. TX and southwards]
(c) Campos, Aidan
    3 Fruits with leathery or soft flesh, 2.5-8 cm long; leaf surface waxy, shiny; leaves persistent all along trunk; [e. TX and eastwards].
(c) Bradley, Keith
(c) Cressler, Alan M.
(c) Weakley, Alan - CC0
      4 Leaf margins minutely notched-serrulate, particularly toward the base; seeds 2.5 mm thick, marginless
(c) Fleming, Gary P.
      4 Leaf margins entire, smooth, hyaline-brown or hyaline-yellow; seeds ca. 1 mm thick, margined.
(c) Fleming, Gary P.
(c) Sorrie, Bruce A. - CC-BY
        5 Leaf blades rigid, straight; inflorescences extending beyond rosettes; fruits pendent, 5.5-8 cm long; [of NC south to FL]
(c) Weakley, Alan
(c) Weakley, Alan
        5 Leaf blades (some or all) recurved, flexible; lower portions of inflorescences included within rosettes; fruits generally erect, 2.5-4.5 cm long; [GA and westwards]
(c) Hill, Sonnia
1 Plants acaulescent (with a cluster of basal leaves) or with a short stem < 3 dm tall above ground level and clothed with numerous leaves (no part of the aerial stem nonleafy and obviously visible, mostly Yucca constricta).
(c) Campos, Aidan
          6 Leaf margins not fraying from the leaf as stiff threads, minutely notched-serrulate or entire, and hyaline, in shades of yellow, orange, or reddish.
             7 Mature leaves undulate-margined, twisted longitudinally; upper leaf surface strongly concave near its midpoint; [c. TX]
             7 Mature leaves straight-margined, not twisted; upper leaf surface flat or slightly concave near its midpoint (becoming more concave near the tip); [c. and e. TX and w. LA].
(c) Hill, Sonnia
(c) Hill, Sonnia
(c) Hill, Sonnia
               8 Plants solitary; leaves (3-) 3.5-6.5 cm wide; young leaves glaucous becoming olive or yellowish-green with age; inflorescence axes woolly pubescent; inflorescence branches recurved or drooping; [e. TX and w. LA]
(c) Campos, Aidan
               8 Plants solitary or forming of up to 30 rosettes via branching subterranean caudices; leaves 1-3.2 (-4.5) cm wide; mature leaves green or persistently blue-green glaucous; inflorescence axes glabrous or pubescent; inflorescence branches spreading or ascending; [c. and nc. TX or se. TX]
© Thomas Adams
                 9 Plants solitary or forming colonies of 2-10 rosettes; leaves 1-2.5+ cm wide; mature leaves green, with margins reddish-brown and smooth; [coastal se. TX]
(c) Campos, Aidan
                 9 Plants forming colonies of 10-30 rosettes; leaves (1-) 2.5-3.2 (-4.5) cm wide; mature leaves persistently blue-green glaucousolive or yellowish-green, the margins yellowish and minutely dentate; [c. and nc. TX]
(c) Bradley, Keith
(c) Sorrie, Bruce A. - CC-BY
(c) Campos, Aidan
          6 Leaf margins entire, usually fraying from the leaf as stiff white, gray, or fulvous (tawny reddish) threads.
(c) Cressler, Alan M.
(c) Campos, Aidan
                   10 Inflorescence usually unbranched and raceme-like or with 1 or 2 short, spreading branches near base, borne below to just above leaf tips.
(c) Campos, Aidan
(c) Hill, Sonnia
                     11 Inflorescences 3-6 (-8) dm, emerging above leaves; leaf blade 0.7-2.5 cm wide, flexible; [more widespread in AR, e. OK, and TX]
(c) Sorrie, Bruce A. - CC-BY
(c) Cressler, Alan M.
                     11 Inflorescences 5-10 dm, usually emerging within leaves; leaf blade 0.8-1.2 cm wide, rigid; [rare in Cross Timbers Region of OK]
                   10 Inflorescence a much-branched panicle, borne well above the tips of leaves.
(c) Bradley, Keith
                       12 Leaves lanceolate or spatulate, or linear-lanceolate, the leaf margins grayish or brownish when fresh with conspicuous marginal threads; [native east of the Mississippi River, occasionally cultivated and escaping westward].
(c) Stuart, Will
(c) Bradley, Keith
                          13 Inflorescence branches glabrous; leaves 2-6 cm wide, stiff, the apex acute-acuminate to obtuse, often concave upward at the apex, the marginal fibrils usually elongate and intertwining (to 20 cm long); [usually near the coast on sandy soils]
(c) Fleming, Gary P.
                          13 Inflorescence branches usually scurfy-pubescent or occasionally glabrous; tepals 3-5 cm long; leaves 1.5-4 cm wide, pliable, the apex attenuate-acuminate, not notably concave, the marginal fibrils usually short (to 4 cm long); [more common inland, and on a variety of soil types]
(c) Wong, Michelle - CC-BY
                       12 Leaves linear or linear-spatulate, white-margined when fresh with usually fewer marginal threads or smooth; [native west of the Mississippi River].
(c) Weakley, Alan - CC0
(c) Wong, Michelle - CC-BY
                            14 Leaves very slender, 0.8-1.5 cm wide, 100-200 per strikingly globose rosette; fruit usually constricted near middle; [limestone, granite, and clayey substrates]
© Sonnia Hill
                            14 Leaves usually 1.5-4 cm wide, ca. 50-85 per rosette (rosette not globose in appearance); fruit constricted or not so; plants of sandy substrates.
© Sonnia Hill
© Sonnia Hill
© Sonnia Hill
                              15 Panicle branches smooth glabrous with glaucous glaze; scape 1-1.8 m. high, slender (4-5 mm. thick at base of inflorescence); leaves relatively wide (to 4 cm), rather soft and limp, relatively few leaves in rosette (10-30); flowering mid-June-July
© Sonnia Hill
                              15 Panicle branches glabrous or pubescent but without glaucous haze, rosettes larger (50-85 leaves); scape 1-4 m high (5-10 mm. or more thick at base of inflorescence); leaves various widths but rather rigid and stiff; flowering May-mid-June.
© Sonnia Hill
© Sonnia Hill
                                16 Inflorescences glabrous; leaves relatively wide, (1.5-) 2-4 cm wide and strongly glaucous; capsules large, to 6 cm long; [endemic to nc. TX]
(c) Hill, Sonnia
                                16 Inflorescences pubescent, puberulent, or glabrous; leaves usually narrower, 1-2(-4) cm wide, green or occasionally glaucous; capsules smaller, 2.5-4 cm long (to 6 cm long for rare Y. tenuistyla).
(c) Hill, Sonnia
(c) Hill, Sonnia
                                  17 Inflorescences usually densely pubescent (rarely glabrous or puberulent); style tumid and greenish, yellowish, or creamy white; leaves 1.5-3 (-4) cm wide; [more widespread west of the Mississippi River]
                                  17 Inflorescence glabrous or puberulent; style oblong, white, and occasionally deeply parted; leaves 1-2 cm wide; [very rare along se. TX coast]