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Published In: Nova Genera et Species Plantarum seu Prodromus 30. 1788. (20 Jun-29 Jul 1788) (Prodr.) Name publication detailView in BotanicusView in Biodiversity Heritage Library
 

Project Name Data (Last Modified On 9/15/2021)
Acceptance : Accepted
Note : Tribe Hamelieae
Project Data     (Last Modified On 4/9/2020)
Notes:

The Neotropical genus Hoffmannia includes perhaps about 100 species of herbs, subshrubs, and straggly shrubs found widely in the understory of humid vegetation. Hoffmannia is characterized by a generally succulent or very brittle habit; opposite or verticillate leaves; deciduous, generally triangular stipules that are interpetiolar or shortly fused around the stem; axillary cymose inflorescences; bisexual, homostylous flowers with four calyx lobes, four stamens, and four corolla lobes that are imbricate in bud; generally pink, orange, red, or yellow, rotate or salverform to funnelform, medium-sized to small corollas; generally 2- to 4-locular ovaries; and berry fruits that are variously colored at maturity and contain numerous small, angled seeds. In many species the plants are unbranched and rather succulent, and frequently ca. 1 m tall; several species form branched shrubs, but with long, little-branched stems. The stipules are often succulent and somewhat divergent from the stems and ornate in form and/or glandular, although these distinctive stipules are not usually evident in dried specimens and has therefore often been overlooked. Hoffmannia has its main center of species diversity in southern Mexico and Central America, and another center of diversity in the northern Andes. The genus is distributed continuously from Mexico through Central America and western South America to Bolivia, and across northern South America through Venezuela, and also has one (or possibly two) disjunct species in the Atlantic forest of eastern Brazil to northern Argentina.

Hoffmannia belongs to the tribe Hamelieae, which incudes Hamelia, Deppea, and Hoffmannia, all with centers of species diversity in southern Mexico and northern Central America, plus several other small genera found in this region and perhaps Patima. Hoffmannia has been reported from the Guianas, but those reports appear to be based on misidentifications of Patima (see Rubiaceae Project web page for Patima for more information about that genus). Hoffmannia has not been studied comprehensively, and no infrageneric classification has been published. The name Hoffmannia was also used separately by Willdenow for species of Psilotum; those names are not databased here.

Hoffmannia is similar vegetatively to Hamelia, and these are sometimes confused; however Hamelia differs in its terminal inflorescences and five-locular fruits and ovaries. Hoffmannia is very similar to Notopleura, including in its unbranched fleshy habit, the succulent ornamented stipules, and the size and form of the flowers and fruits; however Notopleura differs in its corolla lobes that are valvate in bud, its fruits with two hard pyrenes, and its inflorescences that are terminal (in the epiphytic species) or pseudoaxillary, i.e., borne in only one axil of each stem node, vs. truly axillary (borne in both axils) in Hoffmannia. Hoffmannia is also similar to Patima of the Guianas, which has valvate corolla aestivation.

Several species of Hoffmannia have leaves that are dark and velvety above, and/or marked with white veins or other colors, or bullate; these apparently are characteristically found in dark understory sites. However Castillo-Campos et al. (2014) documented with field work and a common garden a variation within one species in this feature, from uniformly green leaves to dark leaves with white veins, in the understory species Hoffmannia refulgens (as "Hoffmannia rzedowskiana"). Several of these dark-leaved species are cultivated as ornamentals, in particular Hoffmannia ghiesbrieghtii of Mexico and Guatemala. Inflorescences of Hoffmannia species are generally few- to several-flowered, shortly cymose on short peduncles, and often congested or compact; however a few species have well developed peduncles and larger inflorescences. Taylor & Gereau (2011) regarded inflorescence arrangement as less variable within a species, and consequently circumscribed species more narrowly, than done by previous authors. Corolla size varies markedly within a number of Hoffmannia species, but the relative length of the corolla tube vs. the corolla lobe seems to be consistent (at least as to whether the lobes are much longer than, or about equal to to shorter than the tube). The term "rotate" is regularly used for Hoffmannia flowers that have the tube much shorter than the lobes. The fruits are usually fleshy, but in some species mealy and rather dry, and occasionally apparently ar dry and indehiscent. In some cases the locule walls of the fleshy fruits are rather stiff and may resemble pyrenes that contain numerous small seeds, similarly to the fruits if Gonzalagunia and some other genera. Kiehn (1986, 1995) has documented polyploidy within species of Hoffmannia, as well as within-species chromosome number variants that are not multiples but some other type of aneuploidy.

A group of Hoffmannia species found in Central America and adjacent northwestern Colombia are notable in their leaves that have enlarged folded and enclosed portions of the leaf blade that form ant vesicles, situated at the base of the blade, where it connects to the petiole. These were long treated as one species with broadly variable morphology, Hoffmannia vesiculifera Standl., or as two or three closely related species, but Taylor & Gereau (2011) studied this group and recognized eight species. For a key to the species with ant vesicles, see the notes for Hoffmannia vesiculifera.

Author: C.M. Taylor.
The content of this web page was last revised on 10 August 2016.
Taylor web page: http://www.mobot.org/MOBOT/Research/curators/taylor.shtml

 

Distribution:

Humid to usually wet forest, lowland to montane habitats, from northern Mexico, Jamaica, and the Lesser Antilles to Venezuela, Bolivia, and northern Argentina. Hoffmannia cuneatissima ranges the furthest north, into northern Mexico, and is found in perhaps the dryest vegetation for the genus; Hoffmannia excelsa also ranges into northern Mexico, in somewhat more humid areas. One species is found in Jamaica, and one species is currently documented in the Lesser Antilles although two species have been reported from there.

References:

 

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Based on Taylor & Gereau (2011: p. 99)

Soft to suffrutescent herbs, shrubs, or infrequently small trees, terrestrial and sometimes apparently stoloniferous, unarmed,with raphides in the tissues, fleshy to succulent. Leaves opposite or in verticils of 3--4, sessile to petiolate, entire, with the higher-order venation not lineolate, without acarodomatia in the vein axils but occasionally with paired swollen ant vesicles at base of blade; stipules interpetiolar or shortly fused around stem, subtruncate to triangular or rarely 2-lobbed, often with a pyramidal or ornamented medial projection, sometimes glandular, in bud valvate or perhaps imbricated, deciduous or sometimes with truncate basal portion persisting at least shortly after upper portion has fallen. Inflorescences axillary at nodes with and/or below leaves, capitate to glomerulate, fasciculate, congested or laxly cymose with axes often monochasial and cincinnoid, few- to multiflowered, sessile to pedunculate, bracteate or bracts reduced. Flowers sessile or pedicellate, bisexual, homostylous, apparently protandrous, generally small, perhaps fragrant, apparently diurnal; hypanthum turbinate to ellipsoid; calyx limb developed, shortly to deeply 4-lobed, without calycophylls; corolla funnelform, salverform, or rotate, white, yellow, pale green, yellowish green, pink, salmon, red, or purple and sometimes multicolored, internally glabrous, lobes 4, triangular, in bud imbricated simply, alternatively, or quincuncially with all arrangements sometimes found on the same plant (Lorence & Dwyer, 1988), without appendages; stamens (3)4(5), inserted in lower part of corolla tube, anthers narrowly oblong or ellipsoid-oblong, often bright white, deshicent by linear slits, exserted, with connective sometimes prolonged at one or both ends; ovary 2(--4)-locular, ovules numerous, peltate on axile placentas, stigmas 2(--4), linear, clavate, or lancecolate, exserted, often bright white or strikingly colored. Fruit baccate to irregularly capsular, subglobose to elipsoid, fleshy, juicy, spongy, mealy, or ultimately capsular with irregular dehiscence (Lorence & Dwyer, 1988), white, pink, orange, red, or purple-black; seeds numerous, small (generally 0.2-0.3 mm long), irregularly angled, reticulate to foveolate with surface granular between fenestrated walls.

 

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