Monographs Details:

Mori, S. A. & Prance, Ghillean T. 1990. Lecythidaceae - Part II: The zygomorphic-flowered New World genera (Couroupita, Corythophora, Bertholletia, Couratari, Eschweilera, & Lecythis). With a study of secondary xylem of Neotropical Lecythidaceae by Carl de Zeeuw. Fl. Neotrop. Monogr. 21: 1-376. (Published by NYBG Press)

Scientific Name:

Eschweilera Mart. ex DC.

Jugastrum Miers, Neohuberia Ledoux

Description - Understory, canopy, or emergent trees. Inflorescences terminal, axillary, ramiflorous, or cauliflorous, racemes, spikes, or paniculate arrangements of racemes or spikes. Flowers zygomorphic; Calyx-lobes usually six, infrequently four; petals usually six, infrequently four; androecium zygomorphic, the appendages coiled inwards, antherless; ovary usually 2-locular, the ovules usually basal, attached directly to floor of locule or to peg-like placenta from floor of locule. Fruits dehiscent, woody. Seeds often with lateral aril, sometimes without aril, or sometimes with aril completely surrounding seed, the embryo undifferentiated. X=17.


Taxonomic History of Eschweilera

Eschweilera is the largest and most taxonomically complex genus of Lecythidaceae. It was established in 1828 in the Prodromus Systematis Naturalis Regni Vegetabilis. In that work, A. P. de Candolle based E. parvifolia and E. grandifolia on the collections and manuscript names of C. F. P. von Martius who travelled in Brazilian Amazonia from 1818-1820 (Prance, 1971). Although both species clearly belong to what we now consider to be Eschweilera, the genus was based on features that have no generic significance. De Candolle distinguished the genus as follows:

“Omnia Lecythidis, sed calycis limbus retroversus et tubo applicatus plus minus adnatus.—An potius Lecythidis sectio?”

De Candolle’s hesitation in recognizing the genus is emphasized in the last sentence of the generic description where he indicates that it is perhaps better treated as a separate section of Lecythis. However, Martius (1837), as part of his protologue of E. angustifolia (considered by us to be a synonym of E. compressa), argued that Eschweilera was clearly distinct from Lecythis. One of the features given by him to distinguish the genus, the bi-locular ovary, is indeed important in the delimitation of Eschweilera. However, he erred in several other characters. For example, he claimed that the androecium of Eschweilera is similar to that of Lecythis, and that the genus possesses four petals. In the first case, the androecium of Eschweilera is characterized by a unique, fully-coiled androecial hood, the appendages of which are almost always free of anthers. In Lecythis, the androecial hood is usually flat or possesses inwardly curved appendages that do not form a complete coil. The appendages of those species of Lecythis with flat androecial hoods almost always bear some anthers, the pollen of which is often sterile. In the second case, the presence of four petals in Eschweilera is extremely rare, occurring only in three species from southern Brazil (E. alvimii, E. compressa, and E. tetrapetala) and in unrelated species from Venezuela (E. perumbonata) and Brazilian Amazonia (E. amazoniciformis).

Endlicher (1840), who apparently was unaware of the diagnosis by Martius, retained Eschweilera as part of Lecythis. Subsequently, many authors, including Berg (1856, 1857, 1858), who treated the Lecythidaceae as part of the Myrtaceae for Flora Brasiliensis, failed to recognize Eschweilera as a genus separate from Lecythis. It wasn’t until the work of Miers (1874) that Eschweilera was reinstated. Moreover, Miers (1874) provided a list of features that distinguished the genus. Today, we recognize Eschweilera by: a fully coiled androecial hood with antherless appendages, an umbonate ovary summit that has led some workers to call the ovary half inferior, a bilocular ovary, and seeds with a lateral aril.

However, as in many attempts at classification, a few species obscure the boundaries between Eschweilera and Lecythis, and a combination of the preceding characters has to be considered before these problematic species can be placed to genus. For example, several species (E. alvimii, E. compressa, E. fanshawei, E. nana, and E. tetrapetala) do not have the fully coiled androecial hoods typical of Eschweilera but, at the same time, possess the bilocular ovaries and seeds with lateral arils of the genus. On the other hand, several species, e.g., E. congestiflora, E. potaroensis, and E. simiorum have fully coiled androecial hoods, but possess the 4-locular ovaries, and seeds with basal arils of Lecythis. Nevertheless, most species can be clearly placed in either Eschweilera or Lecythis.

Miers (1874) segregated Chytroma from Eschweilera, and recognized 25 species of the former. Niedenzu (1892) merged Chytroma in Eschweilera, but Knuth (1939) accepted Chytroma as a distinct genus, adding several new species. Eyma (1932, 1934), in his careful studies of the Lecythidaceae of Surinam, did not accept Chytroma as a valid genus. In this monograph, we consider Chytroma as a synonym of Lecythis because the type designated by Miers is a species of Lecythis (see Lecythis for further discussion). However, we have realigned some of the species of Chytroma in Eschweilera.

The names attributed by Miers (1874) to Jugastrum represent, for the most part, a unique species we now know as Eschweilera tenuifolia. The exceptions are Jugastrum coriaceum which is based on the leaves and flowers of E. coriacea and the fruits of E. tenuifolia, and Jugastrum poiteaui which is considered by us to be a species of Lecythis.

Eschweilera tenuifolia (i.e., the Jugastrum of Miers) is clearly distinguished from the other species of the genus by the presence of wedgeshaped, angular seeds that germinate from the sides rather than the ends. Miers’s (1874) observation that the original description by Berg (1858) of this unique germination is based on misinterpretation is incorrect. We have observed seedlings of E. tenuifolia with lateral germination on numerous occasions. The ovules of E. tenuifolia tend to be more numerous and attached in more rows to the floor of the locule than is the case in most species of Eschweilera. Nevertheless, the number and attachment of ovules is variable, ranging in a continuum from the type found in E. tenuifolia to the less numerous ovules characteristic of most species of the genus. In addition, there is no way to distinguish the flowers of this species from those of other species of Eschweilera. The observation of Miers (1874: 167) that the appendages of the hood bear anthers similar to those of the staminal ring is in error. Consequently, we consider Miers’s Jugastrum to represent a single species with unique seed germination that we treat as a separate section of Eschweilera.

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