Unlike African Begonias, the vast majority of Neotropical Begonias exhibit anemoballistic distribution. In addition, he critically reviewed the manuscript and especially added valuable data to the descriptions and relationships of the sections. Of the 15 Brazilian or mainly Brazilian sections, five (Enita, Scheidweileria, Solananthera, Trachelocarpus, Trendelenburgia) share a unique seed structure that is characteristic at the section level.
Section Trachelocarpus A . DC
Although variation in seed micromorphology between sections can provide taxonomic information, given the issue of correct identifications and the sometimes complicated nomenclature, detailed comparative studies are most valuable when conducted in close collaboration with taxonomists. Results are presented according to the major geographic distributions of the sections for clarity and are not intended to suggest evolutionary relationships. Seeds of the species within each of these sections can be clearly distinguished from those of all other sections.
Section Solananthera A . DC
Description of seeds of Neotropical Begonia In the descriptions of Neotropical Begonia seeds, we highlight those sections with a characteristic seed structure that is sometimes related to special growth forms or to methods of seed propagation. Of nine remaining sections, the seeds of all or most species have a more regular structure. The periclinal walls of the testa cells are collapsed, with the exception of those at the chalaza of B.
Section Trendelenburgia (Klotzsch) A . DC
OTHER SPECIES OBSERVED (Plate 1 Od,e,g-k).-Seed Structure and Micromorphology: The seeds of the other species observed correspond to those of B. FORMER SECTION Huszia.-Seed Structure and Micromorphology: The seeds of the former type species , B. S E C T I O N Eupeta1um.-Seed Structure and Micromorphology: The seeds of the three collections of the type species, B .
The seeds of the remaining species studied are consistent in their dense cuticular pattern, but show some variation in other characteristics. OTHER SPECIES OBSERVED (Plates 14d,e,g-n, 1 Sa-c).-Seeds of all species observed correspond to the ordinary seed type. OTHER SPECIES OBSERVED (Table 17c,e,f;h-m).-The seeds of the species of this section show some differences in size and micromorphology; seeds of B.
CARIBBEAN SPECIES OBSERVED (Plate 18b,c,e-h,k).-The seeds observed of species native to the Caribbean all belong to the common begonia seed type and more or less resemble B. The seeds of the species observed, all conform to the common begonia seed type; however, the section is not homogeneous in seed structure and shows variation in micromorphological characters. Warburg (1894) classified all Begonia species into African, Asiatic and American sections; However, Irmscher (1 925) was of the opinion-.
The seeds of the above species match well with the seeds of the section Spenanthera. Seed dispersal is mostly anemoballistic, that is, the winged fruit is shaken by the wind and the seeds are gradually released through pores or slits.
Section Scheihveileria (Klotzsch) A . DC
Section Ewaldia A . DC
In many respects they resemble species from the Scheidweileria section, but they differ, among other things, in their feathery tenacity and in the shape and hairiness of the leaves. The cuticular pattern is coarse, a pattern of chalazal cells with short linear or short wavy striae. However, they differ in their warty operculum, smaller size, and the presence of a cuticular pattern with short linear and short wavy to short zigzag striae.
Section Enita Brade
In all observed specimens of the species the chalazal side is flattened, probably due to contact with the pericarp, except B. In all observed specimens the anticlinal walls may be undulating; however, there is some variation in the presence and magnitude of the undulations. The seeds of the collection from Cuba have few collar cells (average = eight), with an average length of 315 µm, and the ratio of collar cell length to seed length is 2.0.
Section Pritzelia (Klotzsch) A . DC
Specimens from Surinam differ in having a prominent chalasa with inflated cells, making the chalasa even wider than the central part of the seed. The cuticular structure of the chalazal cells is more distinct, with more randomly oriented zigzag ornamentation and distinct patches of confluent cuticular pattern. This can be compared, for example, to the collection from Costa Rica, whose seeds have about 10 neck cells in the seed circumference.
Section Philippomartia A . DC
Begonia organensis BRADE (Table 1 8n).-Structure and micromorphology of the seed: The seeds of this species correspond to the ordinary seed type and cannot be associated with any of the groups described above. The seeds have broad anticlines resulting from thickening of the outer periclinal walls adjacent to the anticlines. The seeds of the other three parts have relatively small seeds and show no special characters.
As this research shows, the seeds of the American representatives of section Knesebeckia are quite diverse in structure.
Section Tetrachia Brade
Section Gaerdtia (Klotzsch) A . DC
Section Latistigma A . DC
Section Pereira Brade
Of the twelve Andean sections, five (Casparya, Gobenia, Hydristyles, Rossmannia, Warburgina) have a characteristic seed structure that distinguishes them from all other Neotropical sections.
Section Casparya (Klotzsch) A . DC
Cuticle with so-called double structure: more raised, short zigzag to stellate thick folds and irregular, short zigzag to short linear underlying decoration. 26762 differs slightly from the above collection (Holm-Nielsen et al. 26438) in having less shallow testa cells and a cuticular ornamentation of short linear to short zigzag striae, sometimes with a faint double structure. Cuticular pattern consisting of rather loose, short, undulating striae to more condensed, short zigzag stripes.
Section Rossmannia (Klotzsch) A . DC
The Scott Hoover 443 collection differs from the collection described above (Kill@ & Hazen 9165) by a denser cuticular pattern, consisting of a double structure of mainly long zigzag stripes.
Section Hydristyles A . DC
The section differs from related Andean sections by the presence of five unequal petals and multiform styles in the female flower. The longitudinal anticlinal walls of the collar are straight, those of other testa cells more irregularly curved, sometimes locally corrugated. They differ in shape, seed size and the thickness and undulation of the anticline walls.
Section Warburgina 0 . Kuntze
Cuticular pattern short linear; cuticle locally with patches of thin, somewhat dense linear to wavy striae.
Section Gobenia A . DC
The seeds are even more variable in shape, sometimes somewhat J-shaped and/or slightly distorted.
Section Meionanthera A . DC
The seeds of the other four species examined are also relatively small, not exceeding 400 pm, and correspond to the common begonia seed type. The seeds of the large section Gireoudia all conform to the common begonia seed type and do not show a distinct grouping of the seeds. The majority of the seeds in all seven sections, not restricted to one of the main geographical areas, correspond to the common seed type.
Section Eupetalum (Lindley ex Klotzsch) A . DC., Including the Former
Although some species locally show cuticular striae similar to crow's feet, the seeds lack distinct characteristic features at the sectional level. Furthermore, the seeds show some variation in size, shape of the operculum, thickness of the anticlinal walls and density of the cuticular pattern. Begonia macbrideana has a different cuticular pattern and further differs by having a blunt operculum, a greater number of collar and testa cells, and straight anticlines.
It has the largest seeds observed in the previous Huszia section, with an average size of 455 pm x 300 pm and a length:width ratio of 1.5.
Section Apteron C . DC
Section Barya (Klotzsch) A . DC
Section Pilderia A . DC
The section is characterized by staminate flowers with two to four petals and pistillate flowers with five persistent petals and undivided placentas.
Section Australes Smith & Schubert
The surface of the cuticle can be smooth (section Urnifonnia), weak, pronounced or even form a net-like structure of folds (section Trachelocarpus).
Section Urniformia Houghton ex Ziesenhenne
Section Gireoudia (Klotzsch) A . DC
Later, Gireoudia was considered a subdivision of the Magnusia section along with the Rachia and Psathuron subdivisions. On the basis of priority, Gireoudia is now treated as a section that includes Magnusia and Psaturon. The Central American and Mexican species of the section were revised by Burt-Utley.
The section is characterized by staminate and pistillate flowers with two tepals and pistillate flowers with bipartite placentas. The section includes over 60 species, most of which are endemic and restricted to Mexico and Central America.
Section Hexaptera Ziesenhenne
Test cells more or less polygonal, with straight, curved or sometimes slightly wavy anticlinal walls; thickened anticlinal walls. Cuticular texture variable, from mostly pale linear, to short linear in the McVaugh 10266 collection, to smooth in the collection of Davidse et al. The seeds of the Mc Williams & Molina 42675 collection are comparable in size and shape; however, they differ in having a greater number of collar and testis cells, mostly straight anticlinal walls, and a more distinct cuticular pattern of short zigzag striae.
Section Dissepbegonia Ziesenhenne
Section Podandra A . DC
Section Weilbachia (Klotzsch & Oersted) A . DC
Section Ruizopavonia A . DC
Seeds of the Asian Knesebeckia species also show considerable variation in seed morphology and do not closely resemble the American species of section Knesebeckia or those of section Diploclinium.
Section Doratometra (Klotzsch) A . DC
Section Begonia Baranov & Barkley
As is the case in African and Asian begonias, the seeds of the Neotropical species show considerable diversity in seed size and structure. Of the Brazilian or mainly Brazilian sections, the following five sections have a characteristic seed structure. In section Enita (Wageneria) the micropylar and or chalazal cells of the seeds are unfolded and air-filled, resembling balloons.
Possible relationship between sections Ewaldia and Scheihveileria as suggested by successor of 1894; Irmscher, 1925), is supported by seeds. Seeds of type B. Of the sections mostly confined to the Andes and Guyana regions, five have characteristic seeds. Of the sections mostly confined to the Central American and Caribbean regions and Mexico, only the seeds of the monotypic section Urniformia show special characteristics.
Seeds of the Asian section Diplocliniurn that we observe also correspond to the common Begonia type: they are mostly relatively small and show some variation in anticlinal walls and cuticular structure. The vast majority of Neotropical Begonia species appear to be wind-dispersed (anemochory; see van der Pijl, 1972).