Heart-shaped leaves are 5 cm diameter with palmate venation; staminate flowers show 2 or 3 individual flowers in the apical bud (Dehgan & Webster, 1979), and the pollen grains are spheroidal of 58 [micro]m in diameter inaperturate (Bahadur et al.
All studied varieties (India = IND, Sinaloa = SIN and Baja California Sur = BCS) pollen grains are inaperturate and show crotonoid sculpture; a croton sculpture refers to the presence of polygonal elements (Fig.
A highly interesting observation concerns Sauromatum venosum (Araceae), which has inaperturate
pollen grains with an endexine and spines, both polysaccharidic in nature (Weber et al.
Taxus pollen is inaperturate
, between 20 25 [micro]m.
1 Undetermined trilete spores 2 Gymnosperm pollen Inaperturate
pollen Inaperturopollenites sp.
Because pollen of Xyris is thus far considered to be relatively uniform, and that of other Xyridaceae diagnostic at the generic and possibly lower taxonomic ranks (Carlquist, 1960; Campbell, 2004b), this study emphasizes Xyridaceae with spherical, apparently inaperturate pollen with the aim of assessing pollen characters of potential taxonomic usefulness.
Pollen grains large to very large, 49-180 [micro]m in diameter, spheroidal, and inaperturate (Table 2, Fig.
In addition, the following assemblage of uniquely combined morphological characters suggests that Aristolochia, Asarum, Euglypha, Holostylis, Saruma, and Thottea form a monophyletic group: alternate, distichous leaves with reticulate, palmate venation; adaxial prophylls; oil cells; perianth essentially trimerous; androecium and gynoecium essentially hexamerous; and pollen in monosulcate or inaperturate
is unclear whether this pollen is really inaperturate
Reliable records of this pollen, which is inaperturate
Pollen 2-3-porate, typically barrel shaped (in tetrads and inaperturate
Four main ecological sporomorph groups characterize the samples: (1) gymnospermous inaperturates
and saccates; (2) angiospermous monocotyledons and (3) dicotyledons; and (4) pteridophytic fern spores.