I hypothesize that the morphological features of the exine
coat vary among species and are adapted for a specific dispersal method.
Orbicules provide an interesting model to study sporopollenin biosynthesis since they are a-cellular structures, independent of cytoplasmic control, contrary to the pollen exine
(Clement & Audran, 1993).
His studies indicated that the spores of Asian species have the greatest degree of exine
ridge development, while those of the Hawaiian and Mesoamerican species show an intergradation, with the Mesoamerican species having the least developed ridges.
Stamens included; filaments complanate, lilac toward the apex, the antepetalous ones adnate to the petals for 6-8 mm, the antesepalous ones free; anther base obtuse-sagittate, apex apiculate, apiculus nigrescent, dorsifixed above the base at 1/3 of its length; pollen globose, diporate, exine
psillate; stigma conduplicate-spiral, ellipsoid-capitate, lilac-purple, margins crenulate-lacerate; ovary obconic, trigonous, 8-9 mm long, 6-7 mm in diameter at the apex, white, glabrous, bearing inconspicuous longitudinal sulcus; placentation apical; ovules shortly caudate; epigynous tube inconspicuous, ca.
Identification of clones within four tree fruit species by pollen exine
striata, proteins are located in exine
cavities (tectate grain) as pollenkitt or tryphine.
sculpturing is reticulate and heterobrochate (lumina of different sizes) with some free standing columellae in the lumina (Fig.
Margaret Anderson Bailey of Eugene died May 3 of complications of multiple sclerosis.
Iridescence has been documented from the megaspores of some species of Selaginella, where it is caused by colloidal crystal configuration of the exine
in the spore wall (Hemsley et al.
The pollen tube penetrates the pollen grain's coat through preformed apertures in the exine
Mutisia type, scabrate, 6-8 [micro]m, ectosexine slightly columellate, thick internal tectum.
Pollen prolatesubprolate, medium to large size, tricolporate, exine
Mutisia type, microechinate.
22 x 2 mm appendages adnate to the petals for 18-19 mm, (the distal margins free, the proximal margins adnate to petals for 18-19 mm), the free lobes ovate, 3-4 mm long, apex slightly recurved; stamens completely exposed by the recurved petals at anthesis, suberect; filaments terete, white, the antesepalous ones free, the antepetalous ones shortly adnate to the petals; anthers linear, 7-8 mm long, base sagittate, apex obtuse, fixed near the base, shorter than the petals; pollen narrowly ellipsoid, sulcate, exine
broadly reticulate, lumina rounded, muri narrowed; style exceeding the petals, white; stigma conduplicate, blades subspreading, densely papillose, white, ca.
24 mm; stamens completely exposed by the recurved petals at anthesis, radially disposed; filaments terete, white, the antesepalous ones free, the antepetalous ones shortly adnate to the petals; Anthers linear, 13-15 mm long, base sagittate, apex obtuse, fixed near the base, slightly shorter than the petals; Pollen narrowly ellipsoid, sulcate, exine
reticulate, lumina rounded, muri slightly thickened; style exceeding the petals, white; stigma conduplicate, blades spreading-contorted, densely papillose, white, ca.
Pollen tricolporate or rarely tricolpate, suboblate to prolate, usually of medium to large size (25-100 [micro]m); exine
almost psilate, microechinate to echinate, exine
structure with Anthemoid pattern, x=9.