The Jepson Manual: Higher Plants of California

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  • Up-to-date information about California vascular plants is available from the Jepson eFlora.

Names are linked to treatments from the Manual


Key to OPUNTIA

N.B.: couplets are linked, e.g., 1. is linked to 1'.

  1. Stem segments cylindric to club-like, tubercled; spine epidermis sheath-like, generally deciduous
 
    2. Major spines distinctly flat, epidermal sheath separating only from tip (subg. Corynopuntia)
 
      3. Perianth yellow; largest spine with cross-rows of rough papillae; ovary bristles stiff, with reflexed barbs
O. parishii
      3' Perianth pink-purple; largest spine smooth; ovary bristles hair-like, with ascending barbs
O. pulchella
    2' Spines not flat, epidermal sheath separating from entire spine (subg. Cylindropuntia)
 
      4. Fruit densely spiny
 
        5. Stem < 1 cm diam, tubercle < 2 mm high
O. ramosissima
        5' Stem > 1.5 cm diam, tubercle > 3 mm high
 
          6. Terminal stem segment generally < 2 dm, tubercle length < 2 × width
O. echinocarpa
          6' Terminal stem segment generally > 2 dm, tubercle length > 3 × width
 
            7. Stem generally branched only above; trunk 1
O. acanthocarpa var. coloradensis
            7' Stem generally branched near base; trunks several–many
 
              8. Stem generally < 2 cm diam, filaments green
O. parryi
              8' Stem generally > 2.5 cm diam, filaments red- to green-purple
O. wolfii
      4' Fruit spineless (sometimes with a few deciduous bristles)
 
        9. Fruit generally bearing flowers, perianth purple-red
O. prolifera
        9' Fruit not bearing flowers, perianth yellow, greenish, or red-brown
 
          10. Terminal stem segment > 3 × longer than wide
O. parryi
          10' Terminal stem segment generally < 3 × longer than wide
 
            11. Tubercle length ± = width
O. bigelovii
            11' Tubercle length ± 2 × width
 
              12. Spines 7–10 per tubercle; fruit < 2.5 cm; seeds irregularly shaped, < 3 mm
O. ×fosbergii
              12' Spines 9–16 per tubercle; fruit 2.5–3.5 cm; seeds ± spheric, ± 3 mm
O. ×munzii
  1' Stem segments flat, not tubercled; spine epidermis not separable (subg. Opuntia)
 
    13. Stem generally minutely papillate-hairy, spines 0 (2–8 per areole in c Kern Co.); perianth pink to magenta; filaments red; fresh stigma white
O. basilaris
      14. Spines 2–8, rigid, < 2.6 cm; rare, c Kern Co.
var. treleasei
      14' Spines 0 (barbed bristles present)
 
        15. Stem segment length < 2 × width, width > 5 × thickness
var. basilaris
        15' Stem segment length > 2 × width, width < 2 × thickness
var. brachyclada
    13' Stem glabrous, generally bearing spines; perianth generally yellow to dull red (rarely pink); filaments white, yellow, red, or pink; fresh stigma green; not in Kern Co.
 
      16. Terminal stem segment easily detached, < 3.5 cm, width < 3 × thickness; w High Cascade Range (Siskiyou Co.)
O. fragilis
      16' Terminal stem segments firmly attached when fresh, > 4 cm, width > 4 × thickness; mostly Southwestern California, Desert
 
        17. Fruit becoming dry, tan, generally spiny; perianth yellow to pink-magenta; style slender, white, base slightly thicker
O. erinacea
          18. Ovary spiny; spines generally in all stem areoles; smaller spines at lower edge of stem areole 3 or more, strongly reflexed
var. erinacea
          18' Ovary spineless; spines in < 50% of stem areoles; smaller spines at lower edge of stem areole 0–4, ± reflexed
var. utahensis
        17' Fruit juicy, generally with some deep purple, spines 0; perianth yellow, orange, or red; style thick, white to red, base much thicker
 
          19. Trunk 1, erect; areoles generally > 38 per ovary
 
            20. Mature plant > 3 m; stem bristles < 1 mm, inconspicuous; ovary clearly tubercled when fresh
O. ficus-indica
            20' Mature plant < 2.5 m; stem bristles 2–12 mm, conspicuous; ovary smooth
 
              21. Longest spines generally 32–47 mm; style white when fresh; seed 3 mm; se California Floristic Province, Desert
O. chlorotica
              21' Longest spines 19–25 mm; style red or pink when fresh; seed 3.5–4 mm; w California Floristic Province
O. oricola
          19' Basal branches several, ± decumbent to ascending; areoles < 36 per ovary
 
            22. Style and filaments white
 
              23. Stem segment > 15 cm wide; perianth base yellow; fruit red inside
O. engelmannii var. engelmannii
              23' Stem segment < 14 cm wide; perianth base red; fruit green inside
O. phaeacantha
            22' Style pink or filaments yellow (or both)
 
              24. Stem segment > 15 cm wide
O. ×occidentalis
              24' Stem segment < 15 cm wide
 
                25. Stem segment oblong-elliptic or narrowly obovate; major spines generally round, 4–11 per areole
O. littoralis
                25' Stem segment obovate; major spines generally flat, 1–4 per areole
O. ×vaseyi


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