Aloes and Lilies of Ethiopia and Eritrea

38 ALOES AND LILIES OF ETHIOPIA
What is a lily?
Lilies in the widest sense are recognised by their 6 more or
less equal, often showy, tepals, without differentiation into
sepals and petals. Until the first edition of ‘The families of
flowering plants’ (Hutchinson 1934), the delimitation of
families within Liliflorae – i.e. lilies in the widest sense –
was fairly simple: 6 stamens and perianth situated below
the ovary (hypogynous) meant that the plant belonged to
the family Liliaceae; 6 stamens and perianth above the
ovary (epigynous) meant Amaryllidaceae; and 3 stamens
and perianth above the ovary meant Iridaceae.
This simplistic system started to collapse
when Hutchinson proposed to restrict the family
Amaryllidaceae to include only bulbous plants with an
umbellate inflorescence. In the African flora, this lead
to the recognition of an additional family, Hyp o xi daceae,
with corms/tubers and a ± racemose inflorescence.
All information obtained later, from chemistry,
micromorphology and molecular data, supported this
delimitation, showing that epigynous flowers within the
Liliflorae have developed more than once. In the New
World, the more restricted definition of Amaryllidaceae
lead to the recognition of Alstroemeriaceae and Agavaceae
– the latter represented in Africa by introduced species of
Agave. Iridaceae has, on the other hand, remained fairly
constant since its description by Jussieu in late 18th
century.
The splitting of the family Liliaceae started rather
late. In their book ‘The families of the monocotyledons’,
Dahlgren et al. (1985) proposed to split Liliaceae into
more than 20 new families, which were further placed
in 5 different orders (Asparagales, Burmanni ales,
Dioscoreales, Liliales, and Melanthiales). The family
Liliaceae itself is in fact no longer represented by any
indigenous taxa in Africa south of the Sahara – only
by intro duced representatives of the genus Lilium. The
family in its widest sense has rather conservative and
primitive flower structures. With cladistic terminology
we might say that the family in its traditional
circumscription constituted a huge paraphyletic (possibly
even poly phyletic) assemblage, defined only by primitive
(plesiomorphic) traits. Such families have to be redefined
to give monophyletic entities.
In recent publications of Floras of tropical Africa, this