Comparative pollen morphology and taxonomic ... - CNCFlora

96 R.L.B. de Borges et al. / Review of Palaeobotany and Palynology 154 (2009) 91–105
Spiraperturate pollen grains with a spinulose exine surface are
especially characteristic of the family among those from the same
order (Kuprianova, 1948; Erdtman, 1952; Raj and Saxena, 1966;
Sharma, 1967; Maley, 1970; Melhem and Abreu, 1981; Zavada, 1983;
Salgado-Labouriau and Rinaldi, 1990; Wanderley and Melhem, 1991;
Harley and Zavada, 2000; Linder and Rudall, 2005).
According to Ruhland (1903), the family includes two subfamilies:
Eriocauloideae (Eriocaulon and Mesanthemum) with four or six
stamens and glandular petals and Paepalanthoideae (the remaining
genera) with two or three stamens and non-glandular petals. This
proposal, although not corroborated by morphological analyses
(Giulietti et al., 2000), was supported by molecular analysis (M. J. G.
Andrade, unpubl. data) and now by our pollen data.
Eriocaulon differs from the other genera by having interapertural
exines arranged in a two-by-two pattern and in displaying an exine
with obtuse microspines and an ornamented apertural membrane.
Mesanthemum, the other genus of the subfamily Eriocauloideae,
Plate I. Pollen grains of Eriocaulaceae.
1–5. Eriocaulon elichrysoides Bong., 1 — high focus, 2 — optical section, 3 and 4 — general view (SEM), 5 — surface (SEM).
6. Eriocaulon humboldtii Kunth., surface (SEM).
7–9. Actinocephalus bongardii (A. St.-Hil.) Sano, 7 — high focus, 8 — optical section, 9 — low focus.
10–12. Actinocephalus divaricatus (Bong.) Sano, 10 — high focus, 11 — optical section, 12 — low focus. All bars=2 µm.
Plate II. Pollen grains of Eriocaulaceae. (see on page 98)
shows medium-sized pollen grains (ca. 35 µm), echinate exine, and
apertures in spiral form (see Ybert, 1979).
Tonina and Syngonanthus stand out from the other genera within the
subfamily Paepalanthoideae. Tonina fluviatilis, however, presented a
unique character (grooved spines) within the Eriocaulaceae, confirming
its position as a monotypic genus, which is now sustained by pollen data.
The pollen grains of Syngonanthus have two differential aperture
patterns. In S. sect. Syngonanthus (S. fuscescens and S. schwackei), S. sect.
Carpocephalus (S. caulescens), and S. sect. Thysanocephalus (S. cipoensis
and S. vernonioides) these are spiraperturate, while in the species of
Syngonanthus sect. Eulepis and in S. imbricatus [S. sect. Thysanocephalus,
which was recently proposed to be included in S. sectEulepis by
Lazzari (2000)] they are 2-zonasulcate. This latter type of aperture, here
discovered in Syngonanthus, is especially interesting because the genus
forms two monophyletic groups based on morphological, molecular
(M. J. G. Andrade, unpubl. data.) and flavonoid data (Ricci et al., 1996):
Group 1 — Syngonanthus sect. Syngonanthus together with S. sect.
1–2. Actinocephalus cabralensis (Silveira) Sano, 1 — general view (SEM), 2 — surface (SEM).
3–6. Actinocephalus ramosus (Wikstr.) Sano, 3 — general view (SEM), 4–6 — surface (SEM). 7–11 — Blastocaulon albidum Ruhland,; 7 — high focus, 8 — optical section, 9 —
low focus, 10 — general view (SEM), 11 — surface (SEM).
12. Blastocaulon scirpeum (Mart.) Giul., surface (SEM). All bars =2 µm.
Plate III. Pollen grains of Eriocaulaceae. (see on page 99)
1–6 — Lachnocaulon minus Small, 1 — high focus, 2 — optical section, 3 — low focus.
4 — general view (SEM), 5–6; surface (SEM).
7–11. Leiothrix hirsuta (Wikstr.) Ruhland, 7 — high focus, 8 — optical section, 9 — low focus, 10 — general view (SEM), 11 — surface (SEM).
12. Leiothrix plantago (Mart.) Giul. general view (SEM). All bars=2 µm.
Plate IV. Pollen grains of Eriocaulaceae. (see on page 100)
1–3. Leiothrix plantago (Mart.) Giul., 1 — surface (SEM), 2 — general view (SEM), 3 — surface (SEM).
4–6. Leiothrix curvifolia (Bong.) Ruhland, 4 — high focus, 5 — optical section, 6 — low focus.
7–9. Paepalanthus applanatus Ruhland, 7 — high focus, 8 — optical section, 9 — low focus;
10. Paepalanthus pulvinathus N. E. Br., surface (SEM).
11–12. Paepalanthus scleranthus Ruhland, 11 — general view (SEM), 12 — surface (SEM). All bars =2 µm.
Plate V. Pollen grains of Eriocaulaceae. (see on page 101)
1. Paepalanthus subtilis Miq., surface (SEM).
2–12. Philodice hoffmanseggii Mart., 2 — high focus, 3 — optical section, 4 — low focus; 5 — high focus, 6 — optical section, 7 — low focus; 8 — high focus, 9 — optical section, 10 —
low focus; 11 — general view (SEM), 12 — surface (SEM). All bars=3 µm.
Plate VI. Pollen grains of Eriocaulaceae. (see on page 102)
1–6. Rondonanthus duidae (Gleason) Hensold & Giul., 1 — high focus, 2 — optical section, 3 — low focus, 4 — general view (SEM), 5–6 — surface (SEM).
7–9. Syngonanthus mucugensis Giul., 7 — high focus, 8 — optical section, 9 — low focus.
10–11. Syngonanthus giuliettiae L. R. Parra, 10 — general view (SEM), 11 — surface (SEM).
12. Syngonanthus schwackei Ruhland, surface (SEM). All bars =3 µm.
Plate VII. Pollen grains of Eriocaulaceae. (see on page 103)
1 — Syngonanthus arenarius (Gardn.) Ruhland, surface (SEM).
2–6. Syngonanthus vernonioides (Kunth.) Ruhland, 2 — high focus, 3 — optical section, 4 — low focus, 5 — general view (SEM), 6 — surface (SEM).
7–12. Tonina fluviatilis Aubl., 7 — high focus, 8 — optical section, 9 — low focus, 10 — general view (SEM), 11 — surface (SEM), 12 — spine (SEM). Arrow = microspine on apertural
membrane. All bars=3 µm except Fig. 12=1 µm.