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Literature review
Species belonging to Romulea are deciduous perennial geophytes (DE VOS, 1972;
MANNING & GOLDBLATT, 2001).The tunicated corms of these plants enable them
to survive the dry season (DE VOS, 1972). At the start of the growing season a group
of adventitious roots are first formed near the base of the corm after which the top
axillary bud develops into a inflorescent stem (DE VOS, 1972). During growth the
corm gradually shrinks and a new corm is formed, which remains dormant until the
next season (DE VOS, 1972).
Most of the species used in this study generally occur in seasonally moist or
inundated open sandy or clay flats (MANNING & GOLDBLATT, 2001). The genus
Romulea is not as substrate-specific as many other southern African Iridaceae and in
Romulea sp. true edaphic endemics are rare (MANNING & GOLDBLATT, 2001).
These edaphic endemics include most of the species endemic to the western Karoo,
which is found only in fine-grained doleritic clay soil and R. barkerae, which is
restricted to the coastal limestone deposits of the Saldanha district (MANNING &
GOLDBLATT, 2001).
The corms of species belonging to Romulea are described by as globose, bell-
shaped or asymmetrical and woody (MANNING & GOLDBLATT, 2001). The corm
consists of a few swollen, basal internodes of the axis covered by the tunics, which
consists of persistent leaf bases (DE VOS, 1972). DE VOS (1972) noted that the
adventitious roots of species belonging to this genus originate from a basal ridge or
basal point on the corm in the form of a row or cluster that represents the ventral side
of the rhizome from which the distinguishing corm of the species in the family
Iridaceae evolved (DE VOS, 1972). When the plant is too high in the ground a
contractile root may develop from the basal scar (DE VOS, 1972). This root is thicker
than other adventitious roots (DE VOS, 1972). The new corm is most commonly
obliquely attached to the old corm via the basal scar (DE VOS, 1972). This basal
scar is not quite basal and is actually situated towards one side (DE VOS, 1972). A
new corm develops when a basal internode of the axis develops into leafy shoots
(DE VOS, 1972). The newly formed corms are still partially enclosed in the old corm
tunics after formation (DE VOS, 1972).
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