Nicotiana africana

Nicotiana africana is a species of the genus tobacco (Nicotiana ). It is the only species of the genus, which is native to Africa. Within the genus it is classified Suaveolentes in the otherwise occurring only in Australia section.

Description

Vegetative characteristics

Nicotiana africana is a perennial, bushy -branched plant that grows up to 2.5 meters high and slightly woody at the base. The entire plant is densely hairy with glandular trichomes. The stems reach a diameter of up to 2 centimeters, their coat consists of little - to multicellular trichomes, the tip always consists of a single cell. The basal leaves wither relatively early, at the stems are the leaves towards the tip more dense, but become smaller. The shape of the leaf blade of stem leaves obovate ranges from ovoid to elliptical or upper leaves, it will be 20-38 centimeters long and 8-18 centimeters wide. The base is contracted to wide wings on the run down to a short stalk and half cover it with two ears, but with the upper leaves less conspicuous. Towards the peak, the leaf blade is round. The leaf margin is mainly entire, towards the base, he can often be slightly wavy. The leaf surfaces are also covered with glandular trichomes that have unicellular peaks also occur sparsely hydathodes on.

Inflorescences and flowers

The flowers stand in narrow cylindrical thyrsi, several of which sometimes form a ring -saving total inflorescence. The side branches are double wrapping or winding of ( often only one) five to ten flowers, which are mainly at the tips of the inflorescences. In cultured specimens also part inflorescences of up to 25 flowers can be formed. The flowers are (rarely to 21 ) mm long, glandular- hairy flower stems to 7-15.

The flowers themselves are 3 to 4 inches long, are on the outside densely pubescent glandular, slightly zygomorphic and are not mutually exclusive and in sunshine. The calyx is cylindrical, 10 to 13 (rarely to 15) mm long and busy with triangular, obtuse and slightly uneven shaped calyx lobes. These are about 1/3 as long as the calyx. The basal portion of the crown 9 to 11 millimeters in length, and measures 3 to 4 millimeters. In concealed from the cup area five weak depth, whitish longitudinal channels are formed. The front part of the corolla tube is 23 to 29 millimeters long and widens 4-5 to 6-7 millimeters in diameter. The outside of the corolla tube is filled with light green and glandular trichomes with multicellular heads. The inside whitish green and hairless. The coronary band is crooked on the corolla tube is white in color and measures 6 to 7 millimeters. He is weak, lobed to about 1 /3 of the width with ausgerandeten cloth. The hem of the flower is strong and irregularly bent back.

The stamens are 10 to 12 (rarely 9 to 16 ) mm from the corolla tube also. They occur in three different lengths: A pair is long, a second pair of medium length and the single remaining stamen is the shortest. The starting points of the stamens are in three slightly different heights at the base of the front part of the corolla tube, where the stamens are also somewhat hairy pubescent. The stylus is similar in length to the stamens and is bent in the lower third S-shaped.

Fruit and seeds

The fruit is a broadly ovate capsule, which is 11 to 14 millimeters long and is either just as long as the calyx or slightly protrude above it. The capsule opens with four flaps. The dark brown seeds are 0.7 to 0.9 millimeters long, are wrong conical to pyramidal and have a net-like surface of irregularly curved ribs.

Dissemination and locations

The species is widespread in the Middle Namib and get there before in isolated granite sticks.

System

Within the genus Nicotiana Nicotiana africana is classified in the section Suaveolentes. Molecular biological studies have shown that the nature of the early split probably native to Australia representatives of the section and is to be regarded as a sister taxon of the remaining section.

History of Research

A copy of Nicotiana africana was first collected in 1965 on the Omandumba - West Farm and placed in the collection of the Herbarium in Windhoek. A doublet of Herbarbeleges went to the Botanical Bavarian State Collection. Since the genus Nicotiana was not considered native to Africa, the document was not given much attention since it was assumed that it was a cultured, feral or abducted plant. Nevertheless, some of the seeds were cultivated in the Botanical Garden Munich- Nymphenburg. It turned out that none of the known plant Nicotiana species was assigned to so that they began with more accurate investigations. This could further locations of the species in Namibia are determined to continue morphological and karyological analyzes were performed. Only in 1975 than could be ruled out that it is a hybrid species and the locality in Namibia is located in the natural habitat of the plant, was published by Hermann Merxmüller the first description of the new species in the " Communications of the Botanical Bavarian State Collection ".

Evidence

• Tobacco ( genus )
• Nicotiana