Portlandia includes 6 species of shrubs small trees in Jamaica. These are characterized by regular branching; a generally decussate leaf arrangement; medium-sized leaves; persistent, broadly triangular stipules that are shortly united around the stem; large, axillary, showy flowers with white to red corollas that are plicate in bud; long narrow anthers that are positioned with the slender stigma in the corolla throat; and medium-sized capsular fruits with numerous angled to flatttened, tuberculate seeds. The corollas are 3-22 cm long, and the species vary in corolla color and perhaps floral biology. Unlike many other Chiococceae, the leaves usually have visible, reticulated higher-order venation. The corollas in bud are inflated and plicate, with ten alternatiing folds: the sinuses between the lobes are folded "out", or extruded, while the midribs of the lobes are folded "in". Portlandia is characteristically found in on limestone substrates, and is amenable to cultivation and widely grown in tropical greenhouses and outdoors in tropical areas. Portlandia grandiflora is is the most common species in the wild in Jamaica and in cultivation.
The leaves of Portlandia are often stiff-textured and shiny above, and are petiolate except they are subsessile and clasping at the base in Portlandia harrisii. Moore (1930) detailed the stipule morphology of several of the species. The calyx limb is often well developed, 15--25 mm long, in many of the species but shorter, 2--9 mm long, in others. Corolla size also varies markedly both within the genus and within species. Aiello studied these plants in the field, and for example noted (1979: 103) extensive variation in corolla size, 3--8 cm long so 160%, in Portlandia coccinea that she found was not correlated with geography or other variable features such as leaf shape and size. and she detailed (1979: 104) similar variation in Portlandia platantha. These species differ in flower details, non-fragrant and corollas red with white lines in Portlandia coccinea vs. fragrant with corollas white sometimes tinged with pink in Portlandia platantha, and so presumably these differ in pollination mode so the variation in flower size within Portlandia species seems to be characteristic of the genus. The reproductive biology of this group seems not to have been studied.
Portlandia was described and circumscribed for many years as a widespread genus of several dozen species found in the northern Neotropics, and characterized by rather large corollas that are inflated in bud and have several induplicate lobes and medium-sized capsular fruits. The heroric study of Aiello (1979) analyzed the stipules, flowers, and fruits of species that were sometimes included in Portlandia and related genera, and found notable variation in several features and in particular in placentation and ovule arrangement. She concluded by circumscribing Portlandia more narrowly than done by previous authors, as an endemic genus of Jamaica, and separating several other species into distinct genera.
Aiello (1979) recognized most of the same species treated by Adams (1972), but she synonymized two of the names and also concluded that another name applied to Jamaican plants. In her study of variation in living populations, she found continuous variation in leaf form that linked Portlandia albiflora with Portlandia latifolia, and she synonymized them. She also concluded that the original material of Portlandia plantantha matched plants of Portlandia latifolia from Jamaica and adopted that name for that species. The plants described as Portlandia platantha were from nursery stock in England, and the original origin of those plants was unknown so the name was not clearly associated with any modern plants until Aiello's study. She also noted consistent variation within plants with red corollas with light-colored internal lines, which corresponded to Portlandia coccinea, in leaf form with a geographic pattern, and she separated two varieties and named the localized plants from St. Catherine as Portlandia coccinea var. proctorii.
Subsequently Delprete & Motley (2003), in collaboration with George Proctor and with new molecular data, re-evaluated Portlandia. They again separated Portlandia albiiflora from Portlandia latifolia (as Portlandia platantha), without comment about this taxonomic change, and they re-evaluated the plants Aiello treated as Portlandia coccinea var. proctorii. Their molecular analysis places Portlandia albiflora and Portlandia platantha on a polytomy with most of the other species of the genus. For the Aiello's two varieties, with more material available to them and field study they found consistent differences in corolla size between this and the typical variety and also differences in the form of the corolla, and they concluded by treating Aeillo's variety as a species. Delprete & Motley also supported their conclusion about Portlandia coccinea with a cladogram based on ITS sequences, in which Portlandia coccinea was found to be basal in the genus and separated from the rest of Portlandia, including Portlandia proctorii, with 53% bootstrap support.
Paudyal et al. (2018) then studied the Delprete & Motley's (2003) same set of Portlandia species with more molecular data, and found this genus deeply nested in their Chiococceae and related to several other Antillean genera, notably as sister to Isidorea and their combined claded sister to Catesbaea. Paudyal et al. found a different relationships mamong their Portlandia species, however, with Portlandia coccinea on the terminal subclade of the genus. They again separated Portlandia albiflora from Portlandia platantha, again without comment (and perhaps without fully evaluating this), and found Portlandia albliflora basal on their Portlandia clade but only separated from Portlandia platantha with 0.55 (apparently) Bayesian probability and (apparently) no bootstrap support indicated. Delprete & Motley (2003) noted accurately that they regarded Portlandia as comprising 7 species, and Paudyal et al. listed the same 7 species in their analysis but stated that the genus comprised 6 species, with Delprete & Motley cited as their source for this.
Here, Portlandia proctorii is recognized based on the study of Delprete & Motley (2003), but no convincing evidence has been seen from either Delprete & Motley (2003) or Paudyal et al. (2018, which seems actually to contain confusion on this point) to reverse Aiello's synonymization of Portlandia albiflora and that species is not recognized here.
Vegetatively and in its young fruits, Portlandia is similar to Posoqueria, however Posoqueria has slenderly salverform white corollas, shorter anthers on filaments inserted near the top of the corolla tube, bilobed stigmas, and indehiscent baccate fruits.
Author: C.M. Taylor
The content of this web page was last revised on 27 August 2021.
Taylor web page: http://www.mobot.org/MOBOT/Research/curators/taylor.shtml