Aloes and Lilies of Ethiopia and Eritrea

Description
Habitat and
distribution
Aloe trigonantha
Description
ALOE
83
green leaves with fine distinct longitudinal lines and by
almost lacking marginal teeth.
Prostrate or pendent shrub, mostly unbranched, stem up to 1 m
long, ca. 8 cm thick, sometimes branching dichotomously within
leaf rosette, especially when cultivated. Leaves 35–50 in dense
rosette, arcuate, up to 50 × 12 cm, pale blue green, slightly glaucous
(turning purple when old), with fine but distinct longitudinal lines
and, especially in the dry season, with red margins, leaf sap becomes
purple when exposed to air. Marginal teeth almost obsolete, up to
3 per 10 cm, 0.2–0.3 mm long, hardly visible. Inflorescence at first
descending, then ascending so it becomes ± U­shaped, branched
with 3–6(–11) erect racemes. Racemes 12–28 cm long, lax (3–5
flowers per cm). Bracts ovate, 8–9(–15) × 7–8 mm, acuminate,
rather fleshy. Pedicels 8–12 mm long. Perianth cylindrical, 32–33
mm long, 6–8.5 mm wide when pressed, red; outer lobes free for
c. 20 mm.
The species grows on steep basalt slopes or cliffs with
sparse cover of evergreen bush land between 2500 and
2750 m in Gonder, Gojam, Welo, and Shewa floristic
regions. It is so far not known anywhere else. It occurs
in a very sporadic manner, mainly on cliffs, and almost
always in inaccessible places. The main flowering period
is from July to September.
26. Aloe trigonantha Leach
The specific epithet ‘trigonantha’ refers to the threeangled
(trigonus) flower (an thos). The species was
described in 1971 from a plant collected by Macleay in
an area between Bahir Dar and Gonder in Gon der floristic
region and cultivated in Pretoria.
A. trigonantha belongs to a group of aloes (numbers
21–22 and 26–27) which often has secondary branching
(up to 50 racemes or more) and which is usually stemless,
but some old plants may develop thick, prostrate stems.
A. trigon antha is distinguished from the rest of the group
by the three angled perianth with a truncate base.
Rosettes stemless or nearly so. Leaves in a dense rosette, 25–40
× 5–8 cm, uniformly green. Marginal spines 9–10 per 10 cm,
2–2.5 mm high, brown tipped. Inflorescence with 5–50 racemes.
Racemes 8–24 cm long, lax (2–4 flowers per cm). Bracts ovate, 6–8
× 3–4 mm, acuminate. Pedicel 5–10 mm long. Perianth markedly
trigonous with truncate base, 28–33 mm long, 8–11 mm wide near
base when pressed, 7–8 mm wide near mouth, pale yellow to orange
red; outer lobes free for 6–9 mm.