Salzmannia DC.

Jardim, Jomar G., Taylor, Charlotte M., Barbosa, Maria Regina & Pessoa, Maria Do Céo R., 2015, Taxonomic notes on Chiococca and Salzmannia (Rubiaceae, Chiococceae) in northeastern Brazil, with a new combination and a new species, Phytotaxa 202 (1), pp. 15-25 : 20

Salzmannia DC.

Type: Salzmannia nitida DC.

Salzmannia includes two species of trees and scandent to erect shrubs found in coastal forests in northeastern Brazil, one of them newly described here. The genus is characterized by its lack of raphides; resinous exudates generally copiously produced on young vegetative growth and inflorescences ( Fig. 2D ); axillary, subsessile to shortly pedunculate, subcapitate to shortly cymose, several-flowered inflorescences; subsessile to shortly pedicellate, homostylous, quite small, four- to six-merous flowers; tubular yellow to orange corollas with the tubes much longer than the lobes; glabrous to pubescent filaments inserted near the base of the corolla; anthers included within the corolla; ovary bilocular; ovules solitary and pendulous from the apex in each locule; bifid stigma with linear lobes; and fleshy, drupaceous, pink to purple fruits with two pyrenes. The composition and origin of the resinous exudates are unknown; presumably these are produced by colleters associated with the stipules, but further study is needed to document this. Müller (1881) presented the most recent taxonomic treatment of this genus. Salzmannia is found mainly in sandy coastal habitats, in restinga or savanna-like vegetation. The restinga is a distinctive formation of humid evergreen forests and thickets growing on nutrient-poor sandy soils along the Atlantic coast of eastern Brazil. This vegetation originated during the Quaternary, when beach sands were deposited in areas that are currently above sea level, and many of its species are endemic to this region and habitat ( Thomas & Barbosa, 2008). The savanna in the northeastern coast of Brazil occurs in patches over faster-draining sandy soils of Tertiary origin, at altitudes of 30–100 m above sea level, often intercalated within forests.

The discovery of this second species of Salzmannia documents new morphological variation for this genus, which is now known to include trees as well as vining shrubs, cymose inflorescences with reduced bracts as well as subcapitate inflorescences with well developed bracts, and dimorphic vegetative and reproductive growth. The dimorphic growth found in S. arborea is unusual though not unknown in Rubiaceae , with the vegetative branches erect with generally larger leaves, and the reproductive branches spreading to drooping or scandent with smaller leaves. The typical growth form of S. nitida resembles the reproductive stems of S. arborea , with the stems of S. nitida generally all weakly ascending to drooping, scandent, or clambering and its leaves similar in size to the smaller leaves of reproductive stems of S. arborea .

Figures

FIGURE 2. Salzmannia arborea. A. Vegetative branch. B. Bark. C. Infructescence. D. Apical bud with resinous exudate, indicated by arrow. (From J.G. Jardim & J.L. Paixão 6458). Photos by Jomar Jardim.