Key to Subgenera and Series of Opuntiacontinued

AA. At least some of the joints flat or compressed Subgenus 3. Platyopuntia

B. Stems perennial, stout or slender.

C. Plants branching from near or at the base, not forming erect, cylindric unjointed trunks; flowers mostly large. D. Epidermis glabrous or pubescent, not papillose-tuberculate when dry.

E. Flowers perfect; petals obovate to oblong.

F. Fruit a juicy berry (exceptions in Series 5, Basilares). G. Joints readily detached.

H. Joints very readily detached; low, mostly small-jointed species. I. Joints little flattened, subterete (transition to

II. At least the ultimate joints distinctly flattened.

J. Ultimate joints or all joints turgid Series 2. Curassavicae (N. A.; S. A.)

JJ. Ultimate joints flat and thin Series 3. Aurantiacae (S. A.)

HH. Joints less readily detached; mostly taller and larger-jointed species Series 4. Tunae (N. A.; S. A.)

GG. Joints not readily detached, persistent.

H. Areoles small, 1 to 2 mm. in diameter, not elevated, mostly close together Series 5. Basilares (N. A.)

HH. Areoles larger, mostly distant.

I. Prostrate or spreading species; joints relatively small. (O. austrina suberect.) J. Joints not tuberculate.

K. Flowers small, brick-red Series 6. Inamoenae (S. A.)

KK. Flowers large, yellow Series 7. Tortispinae (N. A.)

JJ. Joints strongly tuberculate Series 8. Sulphureae (S. A.)

II. Bushy, depressed or tall species.

J. Spines, when present, brown or yellow (white in O. setispina). K. Spines brown, at least at the base or tip. L. Bushy or depressed species.

MM. Fruit large.

N. Spines acicular Series 10. Setispinae (N. A.)

NN. Spines subulate Series 11. Phaeacanthae (N. A.)

LL. Tall species, sometimes with a definite trunk (O. galapageia sometimes depressed).

M. Spines several at each areole Series 12. Elatiores (N. A.; S. A.)

MM. Spines, when present, 1 to few at each areole Series 13. Elatae (S. A.)

KK. Spines, if any, yellow, at least partially. L. Epidermis glabrous.

M. Areoles close together, bearing long brown wool Series 14. Scheerianae (N. A.)

MM. Areoles distant, without long wool . Series 15. Dillenianae (N. A.) LL. Epidermis, at least that of the ovary, pubescent Series 16. Macdougalianae (N. A.)

JJ. Spines, when present, white (or faintly yellow). K. Epidermis pubescent.

L. Spines, when present, acicular Series 17. Tomentosae (N. A.)

LL. Spines several, setaceous, flexible Series 18. Leucotrichae (N. A.)

KK. Epidermis glabrous.

L. Areoles Dearing long, soft hairs Series 19. Orbiculatae (N. A.)

LL. Areoles without long hairs.

M. Joints green or bluish green.

N. Spineless, or with few, usually short, spines Series 20. Ficus-indicae (N. A.; S. A.)

NN. Spiny, at least old joints so Series 21. Streptacanthae (N. A.; S. A.)

FF. Fruit dry, not juicy Series 23. Polyacanthae (N. A.)

EE. Flowers direcious; petals very narrow Series 24. Stenopetalae (N. A.)

DD. Epidermis densely papillose-tuberculate when dry Series 25. Palmadorae (S. A.)

CC. Plants with erect, unjointed trunks, the branches with flat joints; flowers mostly small. D. Flowers small; joints spreading.

E. Joints all flat, relatively thick Series 26. Spinosissimae (N. A.)

EE. Some joints terete, others flat and very thin Series 27. Brasilienses (S. A.)

DD. Flowers large; joints ascending Series 28. Ammophilae (N. A.)

BB. Stems annual, very slender Series 29. Chaffeyanae (N. A.)


Includes the many-jointed species in which none of the joints is at all flattened.


The series consists of a single bushy species, with slender joints, the nearly flat tubercles diamond-shaped and contiguous, the acicular spines, when present, usually only i at an areole.

Continue reading here: Opuntia ramosissima Engelmann Amer Journ Sci II 14 339 1852

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