Aeonium haworthii Hybrids
Perennial or monocarpic; stems trunk-like, 20- c. 80 cm high, c. 1-2 cm diam., not branched or with few branches, with numerous narrow lf scars. Rosettes terminal, usually 10-18 cm diam., flattened except in summer. Outer rosette lvs to 9-(12) × 3.5 cm, 2-4-(5) mm thick, green, obovate or obovate- spathulate, glabrous on both surfaces, slightly concave on upper, flat on lower; margins ciliate, mostly green, sometimes slightly red towards the mucronate apex. Flowering shoots terminal, either the whole plant or the stem bearing the infl. dying after flowering; axis ± stout, usually tall and erect, glabrous, occasionally glabrate, with leaflike bracts usually present at peak flowering. Infl. a broadly pyramidal panicle, obtuse or rounded to flat at top, on main stem usually 12-20 cm long and almost as wide; fls fairly densely arranged, somewhat secund on branches. Calyx lobes 2.5-4 mm long, glabrous, triangular or triangular-lanceolate. Petals (8)-9-10, 8-11 × c. 2-3 mm, linear, linear-elliptic or linear-lanceolate, greenish white, cream, greenish yellow or pale yellow. Stamens of inner whorl 5.5-9 mm long, the outer whorl usually slightly shorter; stamens and carpels whitish, cream, pale green, greenish yellow, or pale yellow. Scales 0.6-1.5 mm long, almost rectangular or rectangular-cuneate, ± truncate or retuse. Seeds 0.6-0.9 mm long, narrowly obovoid-oblong, minutely longitudinally streaked.
S.: Port Hills and Church Bay (Banks Peninsula).
Origin unknown 1988
Steep west-facing slopes on volcanic soils among low open scrub.
FL Sep-Oct.
There are 2 populations of these hybrids and they display considerable variation in plant stature and branching, form of infl., colour of petals, stamens and carpels, degree of pollen sterility (some plants have narrow anthers and no pollen, others have normal anthers and abundant pollen with > 90% viable grains, N. T. Moar, pers. comm.), and size of scales. Features in common are lvs of similar size, shape and colour, glabrous or almost glabrous infls, and pale-coloured petals, stamens and carpels.
Whether these populations are a result of hybridisation in Canterbury or whether hybrid plants were originally imported is unclear, but they are more likely to have originated locally because similar plants have not been seen in cultivation here or found referred to in available works on the genus. It seems evident that A. haworthii is one parent although flowering times overlap little between it and other potential parents; it is common in the areas concerned as well as being well-known overseas as the parent of several hybrids. If they are of local origin, A. arboreum is very likely to be involved because the habit, lf form and infl. shape of the hybrids are often very similar to those of that sp. On the other hand, hybrid plants have glabrous infls and white to pale yellow fls unlike A. arboreum and there is little or no overlap in flowering times between A. arboreum and A. haworthii. The only other sp. wild or cultivated in Canterbury which might be involved is A. undulatum; pyramidal infls suggesting the influence of this sp. occur in a few putative hybrid plants. Also, flowering times in A. undulatum are intermediate between A. arboreum and A. haworthii.
