Warszewiczia includes perhaps seven or either species of large trees found in wet lowland forests, from Mexico and Central America through the southern Antilles and South America across the Amazon basin. Warszewiczia is characterized by its generally relatively large tree habit, tissues without raphides, medium-sized to quite robust petiolate leaves, interpetiolar triangular stipules that are quickly deciduous and twisted around each other in the bud, terminal spiciform to racemiform inflorescences, small protogynous 5-merous flowers that are arranged in short cymes, short calyx limb that sometimes has one very large petaloid lobe, short white to orange, campanulate to tubular corollas about 1.5-6 mm long with short lobes that are imbricated in bud, and small woody capsules that are septicidal and contain numerous small angled seeds. The stipules are twisted to 360° or more in bud, with most of the twisting in their uppermost portion, but these untwist quickly as the leaves expand. The calycophyll or semaphyll in the Rubiaceae is an enlarged calyx lobe, which functions variously for pollinator attraction and/or fruit or seed dispersal. Most but not all species of Warszewiczia have one or a few calycophylls on at least some inflorescences, and these are numerous and regularly in a few species. In Warszewiczia only the terminal flower of the cyme produces a calycophyll, which is stipitate and has an elliptic blade portion that ranges from white or cream to bright red. These structures are well developed, bright red, and showy on the inflorescences of Warszewiczia coccinea, which is cultivated as an ornamental and the national tree of Trinidad a& Tobago. Warszewiczia coccinea is common in native vegetation and flowers much of the year, and is by far the most frequently encountered species of this genus in the wild.
The flowers of Warszewiczia are unusual in Rubiaceae in being protogynous; in most Rubiaceae the stamens dehisce before the stigmas become receptive. In Warszewiczia this order is reversed, and the staminate and pistillate stages of the flower differ markedly in size and form and can be mistaken for two different species. In the pistillate stage the corolla lobes remain mostly closed, and the stigma extends out of the flower and its lobes spread. Later (perhaps the next day) the corolla tube expands both in diameter and length, the corolla lobes spread, and the anthers are exserted and dehisce. Both flower phases are visible on one of the imaged specimens of Warszewiczia coccinea, Hartshorn 1250. Schumann (1889) presented the first comprehensive review of Warszewiczia and noted this variation in style, stigma, and filament length within the genus, but he did not understand the protogynous flowers and considered the lengths of these structures to be species-specific characters. Accordingly he separated several specimens of Warszewiczia coccinea into different species based on their short vs. long the filaments.
In a molecular systematic study Kainulainen et al. (2010; as Condamineeae) found Warszewiczia to belong to their Tribe Condamineeae (now correctly called Tribe Dialypetalantheae), and related to Chimarrhis and some species of Bathysa The only comprehensive taxonomic review of Warszewiczia is that of Schumann (1889: 215-219), which was published before a number of the species were discovered. Taylor & Maldonado (2023) again reviewed the genus, and presented several notes and updates for many of the species but not a new genus treatment.
The small capsular fruits of Warszewiczia open by splitting into two segments along the septum, with the two segments remaining attached at their bases to the infructescence and the disk falling off as a separate piece. Then the septum of each segment opens along its midline and the walls of the fruit spread, pulling the slit open to release the seeds and often separating form the septum along the top so the seeds also can disperse through that area. When calycophylls are developed they persist on the infructescences, and become dry and stiff and probably aid in shaking the capsules to disperse the seeds. Many species characteristically dry with a chocolate-brown color. The capsule dehiscence has been inaccurately described in several cases due apparently to the observation of capsules that have opened prematurely and had pressure applied. In these the disk has fallen off and the capsule has partially split along the septum and then the walls have also started to split. At first glance these capsules resemble the loculicidal capsules of Elaeagia, however in Elaeagia the disk is persistent on the fruits.
Warszewiczia is similar in its tree habit, many flower details, and small woody septicidal capsules, and sometimes in its calycophylls to Chimarrhis and Bathysa; Chimarrhis can be separated by its axillary paniculiform inflorescences, and Bathysa can be separated by its paniculiform inflorescences. Bathysa multiflora of central Peru is not completely known, and may belong to Warszewiczia. Various other Rubiaceae trees with calycophylls have also been confused with Warszewiczia, but differ in their stipule form, larger flowers and capsules.
One striking cultivar has been seen of Warszewiczia coccina, with numerous calycophylls (Lai 1780, NO in LSU).
Warszewiczia is also similar to Elaeagia, which also has protogynous flowers, and these genera have been separated differently by different authors with their delimitations unclear until recently (Taylor, 2001, Taylor & Maldonado, 2023), and some species are here reclassified into th eother genus. Here Elaeagia is cdagnosed following Taylor (2001), Maldonado (2005), and Taylor & Maldonado (2023) by its stipules that are fused around the stem in bud and split between the petioles into two intrapetiolar segments, and its capsules that are loculicidal and often open only through the disk portion, with this disk elongating above the insertion of the calyx limb as the fruits develop. Accordingly Elaeagia uxpanapensis is here included in Warszewiczia, and Warszewiczia ambigua belongs to Elaeagia.
Author: C.M. Taylor.
The content of this web page was last revised on 23 March 2023.
Taylor web page: http://www.mobot.org/MOBOT/Research/curators/taylor.shtml