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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 12/6/2012)
Acceptance : Accepted
Project Data     (Last Modified On 12/8/2012)
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.

Hoffmannia belongs to the tribe Hamelieae, which incudes Hamelia, Deppea, and Hoffmannia, all with centers of species diversity in southern Mexico and northern Centra America, plus several other small genera found in this region. 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.

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.

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. Several of these 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 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.

C.M. Taylor XII 2012

Distribution: Humid to usually wet forest, lowlands to montane habitats, Mexico, Jamaica, and the Lesser Antilles to Venezuela, Bolivia, and Argentina.
References:

 

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

Soft to suffrutescent herbs, shrubs, or infrequently small trees, with raphides, unarmed, glabrous or variously pubescent, sometimes unbranched, sometimes apparently stoloniferous, often fleshy and rather succulent. Leaves opposite or sometimes in verticils of 3-4, sessile to petiolate, thin-textured or fleshy in life and drying thin-textured, infrequently bullate, without acarodomatia in the leaf axils but occasionally with paired swollen vesicles at base of blade; venation eucamptodromous or brochidodromous, higher-order venation not lineolate; stipules interpetiolar or shortly fused around stem, deciduous or sometimes with truncate basal portion persisting at least shortly after upper portion has fallen, subtruncate to triangular, sometimes markedly succulent, sometimes with a pyramidal or ornamented medial projection, rarely 2-lobed, infrequently apparently glandular. Inflorescences axillary (i.e., produced in both axils of the node), borne with the vegetative leaves and/or along bare stem below leaves, sessile to pedunculate, capitate, glomerulate, fasciculate, or congested to laxly cymose, bracteate or with bracts reduced, axes dichasial or sometimes becoming cincinnate or scorpioid-racemiform. Flowers bisexual, homostylous, sessile to pedicellate, apparently protandrous, apparently diurnal; calyx limb shortly to deeply 4-lobed; corolla funnelform, salverform, or rotate (i.e., with a narrow cylindrical tube that is significantly shorter than the widely spreading lobes), variously white, yellow, pale green, yellowish green, pink, salmon, red, or purple, internally glabrous, lobes 4, triangular, in bud imbricate variously simply, alternatively, or quincuncially, with all arrangements sometimes found on the same plant (Lorence & Dwyer, 1988); stamens (3)4(5), exserted, inserted in lower part of corolla tube, anthers narrowly oblong or ellipsoid-oblong, often bright white, with connective sometimes prolonged at one or both ends; ovary 2(--4)-celled, ovules numerous, peltate on axile placentas; stigmas 2(--4), linear, clavate, or lancecolate, exserted, often bright white or strikingly colored. Fruits baccate, generally subglobose to elipsoid, fleshy and variously juicy, smongy, meal, or ultimately capsular with irregular dehiscence (Lorence & Dwyer, 1988), at maturity white, pink, orange, red, or purple-black; seeds numerous, small (generally 0.2-0.3 mm long), irregularly angled, reticulate to foveolate, with surfce granular etween fenestrated walls.

 
 
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