In this study, micromorphology of an involucral bract and inner and outer
dimorphic cypselae of the relict Amphoricarpos elegans, endemic from western
Caucasus, is examined using a scanning electron microscope (SEM) and
presented here for the first time. The middle involucral bract is nearly
glabrous, with a reticulate-rugulose surface and an oblong-obtusate mucro.
Both cypselae exhibit similar features, viz., narrowly oblong-cylindrical or
obovate shape with more or less conspicuous longitudinal ribs, an adaxial
detachment area, an asymmetrical carpopodium, absence of a pericarp crown
and a barbate-aristate pappus made up of narrow, subulate, basally smooth
and apically barbate bristles. However, some differences are evident. The
outer cypsela is glabrescent and flattened, with an obscure outline of
epidermal cells lacking an end wall and with a sunken periclinal surface and
striatereticulate structure. Also, the outer cypsela has two entire, narrow,
lateral wings, rounded above; and less numerous pappus bristles in one row.
In contrast to this, the inner cypsela has a distinct outline of the
epidermal cells, which are rod-shaped with a short acute end wall, a swollen
periclinal surface and reticulate structure. The pappus of the inner cypsela
possesses many more bristles organised in two rows (a biseriate pappus).
Also, slightly pentagonal or round nectary remnants are found in the centre
of the upper part of the inner cypsela. The taxonomic value of the analysed
characters is briefly discussed.