Bertholletia excelsa, Bonpland, 1807

Huang, Ya-Yi, Mori, Scott A. & Kelly, Lawrence M., 2015, Toward a phylogenetic-based Generic Classification of Neotropical Lecythidaceae- I. Status of Bertholletia, Corythophora, Eschweilera and Lecythis, Phytotaxa 203 (2), pp. 85-121 : 99-102

Bertholletia excelsa clade (100% BS; Figs. 2A , 7 )

This clade includes only Bertholletia excelsa , which is distributed throughout Amazonia and parts of the Guianas (see Fig. 21 in Prance & Mori, 1990). In the present study, B. excelsa is sister to the Lecythis chartacea clade. It differs from species of that clade by having two calyx lobes (character 16; Fig. 7B ), seeds without an aril (character 47; Fig. 7G ), and a type of secondary indehiscence in which the seed is larger than the opercular opening (character 41; Fig. 7E, F ). Bertholletia excelsa provides good examples of petals pressed against the androecium (character 33; Fig. 7A ) and, as seen in the field or in color images, of the yellow color on the androecial hood at the entrance into the flower. Bertholletia is the only genus of the family with a boney seed testa and the complete absence of an aril ( Fig. 7G ). It does, however, share features with species of the L. poiteaui and L. chartacea clades, including similar androecia with swept in appendages ( Fig. 7D ), 4-locular ovaries ( Fig. 7C ), and long, slender, oblique or geniculate styles ( Fig. 7B ).

Mori & Prance (1990) hypothesized that B. excelsa is related to Lecythis lurida ( Miers 1874: 262) S. A. Mori (1981a: 362) . This hypothesis was based on the following shared characters of the two species ( Mori & Prance, 1990): the presence of cuticular papillae on the abaxial leaf blade surface (character 5; see Fig. 96 in Mori & Prance, 1990), hood appendages swept or curved inward without forming a complete coil (character 31; Fig. 7D ), mature fruits that fall to the ground with the seeds remaining inside (character 40), a unique dehiscence (character 41; Fig. 7E, F ) in Bertholletia , and fruits that do not open at all in L. lurida . The relationship of B. excelsa with L. lurida and related species of the L. poiteaui clade is not supported by this study ( Fig. 3A ).

There are no other species of Lecythidaceae with fruits morphologically similar to those of B. excelsa . The fruits of B. excelsa have thicker and woodier pericarps and are, in fact, dehiscent but the opercular opening is smaller in diameter than that of the seeds, and the operculum falls into the fruit when it dehisces ( Tsou & Mori, 2002) ( Fig. 7E, F ). It has been hypothesized that this type of dehiscence is related to selection for dispersal by rodents, especially agoutis ( Ducke, 1948; Prance & Mori, 1978). In neotropical Lecythidaceae , shifts to different dispersal agents and accompanying morphological changes have occurred a number of times ( Tsou & Mori, 2002). For example, in Allantoma there has been a shift from wind-dispersal facilitated by a unilateral seed wing in most terra firme species to the water-dispersed A. lineata with only a vestigial seed wing ( Huang et al., 2008). Another shift has been from the terra firme dehiscent-fruited, arillate seeded, animal-dispersed L. chartacea to the riverine, indehiscent-fruited, non arillate-seeded, water-dispersed L. rorida O. Berg (1858: 488) ( Kubitzki & Ziburski, 1994). Thus, species of neotropical Lecythidaceae may belong to the same genus even though the morphological adaptations for seed dispersal by different dispersal agents may be quite different.

of the hypocotyl. This monotypic clade is part of the larger Bertholletia clade. Drawings by B. Angell and photo by S.A. Mori.

Other morphological characters that would suggest relationships between B. excelsa and some species of Lecythis may be misleading and are homoplasious on our trees. For example many species of Amazonian Lecythidaceae have thick cuticles and papillae that arise from them, most likely to reduce water loss from the leaves—thus, the presence or absence of papillae should not be given much weight in predicting evolutionary relationships in this family. Even the unique two-lobed calyx ( Fig. 7B ) of B. excelsa is not an absolute indicator of evolutionary relationships because nearly all zygomorphic-flowered neotropical Lecythidaceae (including B. excelsa ) have six calyx-lobe primordia in early floral development (see Fig. 78 in Tsou & Mori, 2007).

Figures

FIGURE 2A. Strict consensus of 66 most parsimonious (MP) trees based on total evidence. Bootstrap values (>50%) are given above the branches.All clades in this figure are part of the Bertholletia clade. The Lecythis pisonis, L. ollaria, Bertholletia excelsa, L. poiteaui, and Corythophora clades of the Bertholletia clade are shown.

FIGURE 3A. One of 66 most parsimonious trees based on total evidence (L = 6134, CI = 0.35, RI = 0.76). Morphological characters are optimized onto the tree using the unambiguous option of Winclada. Supporting characters are shown on branches. White ellipses are homoplasious and black ellipses are non-homoplasious characters.All clades in this figure are part of the Bertholletia clade. The Lecythis pisonis, L. ollaria, Bertholletia excelsa, L. poiteaui, and Corythophora clades are shown.

FIGURE 7. The Bertholletia excelsa clade (see Fig. 45 in Mori & Prance, 1990 for vouchers except for B which is vouchered by Mori et al. 17503). A. Flower showing petals tightly pressed against androecium and turned downward at their apices. B. Calyx, ovary, and style. Note that the calyx consists of two lobes, the ovary is inferior and very short and the style is oblique. C. Cross-section of 4-locular ovary. D. Medial section of androecium showing swept in vestigial stamens and the anterior ligular extension. E. Fruit showing that the opercular opening is smaller in diameter than the diameter of the seeds. F. Operculum. Note that it drops into the inside of the fruit a maturity. G. Seed. This is the only neotropical Lecythidaceae with a ligneous seed coat. H. A seedling. The embryo lacks cotyledons and is mostly composed