Aeonium

Webb & Berthelot

Hist. Nat. Îles Canaries 3(2,1): 184, plates 28–35. 1840 ,.

Etymology: Dioscoridean name for A. arboreum
Treatment appears in FNA Volume 8. Treatment on page 167. Mentioned on page 149, 168.
 TaxonIllustrator 
FNA8 P21 Rhodiola rhodantha.jpegRhodiola
Rhodiola rhodantha
Aeonium
Aeonium haworthii
Sempervivum
Sempervivum tectorum
Yevonn Wilson-Ramsey
Yevonn Wilson-Ramsey
Yevonn Wilson-Ramsey
Yevonn Wilson-Ramsey
Yevonn Wilson-Ramsey
Yevonn Wilson-Ramsey

Shrubs [perennial herbs], not viviparous, [1–] 7–10 [–20] dm, glabrous or pubescent. Stems erect, branched [simple], woody or fleshy. Leaves persistent, crowded in rosettes at ends of branches, alternate, sessile, not connate basally; blade oblong-lanceolate or obovate, laminar to terete, 3–15 cm, fleshy, base not spurred, margins ciliate; veins not conspicuous. Inflorescences terminal cymes. Pedicels present. Flowers erect or spreading, [6–] 7–12 [–16] -merous; sepals connate basally, all alike; petals spreading or erect, distinct or nearly so, cream or bright-yellow; calyx and corolla not circumscissile in fruit; nectaries mostly rectangular; stamens 2 times as many as sepals; filaments adnate on corolla base; pistils erect, distinct or nearly so; ovary base rounded; styles 2+ times shorter than ovary. Fruits erect. Seeds ellipsoidal, ribbed, finely cross-ribbed. x = 18.

Distribution

Introduced; Calif., Asia (Yemen), Africa, Atlantic Islands (especially Canary Islands)

Discussion

Species 31 (2 in the flora).

Aeonium and the other polymerous-flowered Macaronesian Crassulaceae were formerly included in the polymerous-flowered Sempervivum. From studies in DNA and molecular systematics, T. H. M. Mes (1995) concluded that Aeonium and these related genera probably evolved from North African Sedum-like ancestors and are only more distantly related to Sempervivum. He thought that the wide range of growth-forms in Aeonium, including the woody habit, is derived from herbaceous ancestors.

Selected References

None.

Key

1 Rosette leaves 50-75, blade bright green, 5-9(-15) cm, 1.5-3 mm thick; petals 9-11, spreading, bright yellow. Aeonium arboreum
1 Rosette leaves 15-25, blade gray-green, 3-6 cm, 2-5 mm thick; petals 7-9, erect, cream. Aeonium haworthii
... more about "Aeonium"
perigynous +  and hypogynous +
Reid V. Moran +
Webb & Berthelot +
lobed +  and toothed +
terete +, obovate +  and oblong-lanceolate +
3 cm30 mm <br />0.03 m <br /> (15 cm150 mm <br />0.15 m <br />) +
not circumscissile +
whorled +, opposite +  and alternate +
not circumscissile +
Calif. +, Asia (Yemen) +, Africa +  and Atlantic Islands (especially Canary Islands) +
Dioscoridean name for A. arboreum +
[6-]7-12[-16]-merous +
spreading;erect +
axillary +  and terminal +
alternate +  and crowded +
persistent +
connate +
semi-inferior +  and superior +
tenuinucellate +, crassinucellate +  and bitegmic +
perigynous +  and hypogynous +
nearly +  and distinct +
erect +  and spreading +
(3-)4-5(-12)[-30+]-carpellate +
nearly +  and distinct +
Hist. Nat. Îles Canaries +
cross-ribbed +  and ribbed +
ellipsoidal +
1 +  and many +
adnate +  and free +
antipetalous +
2 times as many as sepals +
fleshy +  and woody +
distinct +
2+ times shorter than ovary +
Aeonium +
Crassulaceae +
not conspicuous +
perennial +, biennial +  and annual +
pubescent +  and glabrous +