A pair of internal recessed bilabiate valves, through which the radicle must exit, are formed by the distal parts of the locular envelope within each pore (Fig.
We infer that the seeds germinated with a recessed, bilabiate mechanism.
Lamiales are a huge clade in terms of species, genera and families with monosymmetric, often elaborate bilabiate flowers (Kampny, 1995).
Other cases with stronger monosymmetry are: Sprekelia (Amaryllidaceae), in which, in addition to mere curvature, the perianth is conspicuously monosymmetric (Vochting, 1886); Haworthia and Chortolirion (Asphodelaceae) with bilabiate perianth (Smith & Van Wyk, 1998); Daubenya with three enlarged petals in basal flowers of the inflorescence, and Lachenalia (Hyacinthaceae) with a bilabiate perianth (Speta, 1998); Melasphaerula, Sparaxis, Chasmanthe and perhaps other Iridaceae-Ixioideae with bilabiate or otherwise monosymmetric perianth (Vogel, 1954; Goldblatt et al., 1998); Conanthera, Cyanella, Tecophilaea (Tecophilaeaceae) with strongly monosymmetric androecium (Simpson & Rudall, 1998).
Cabrera defined the Mutisieae as having bilabiate corollas, caudate anthers, and characteristic style shape.
The bilabiate corolla was generally considered the typical form in the Mutisioideae.
The ligulate corolla of Catamixis results unusual for Mutisioideae, where there is a predominance of bilabiate
corollas (although some species of Mutisia have also ligulate florets).
Florets dimorphic or rarely isomorphic; marginal florets female, with staminodes, corolla bilabiate
, outer lip expanded or not, inner lip developed to very reduced, or true ray; central florets bisexual, corolla bilabiate
; or all the florets bisexual, corolla bilabiate
, sub-bilabiate (4+1 corolla lips), or ligulate; anther apical appendages acute, tails smooth; style bilobed, dorsally papillose.
Florets isomorphic or dimorphic, bisexual; marginal florets with corolla bilabiate
, outer lip expanded or not; central florets with corolla bilabiate
; anther apical appendages acute, tails smooth; style bifid, branches apically truncate, crowned by collector hairs.
Florets dimorphic, bisexual, marginal florets with corollas bilabiate
, outer lip expanded; central florets with corollas actinomorphic, tubular-campanulate, deeply five-lobed, tube narrow, abruptly dilated into a limb, lobes coiled; anther apical appendages apiculate, tails papillose; styles bilobed, branches appressed, dorsally sparcely papillose, papillae reaching the bifurcation point.