Nelsonia canescens (Lam.) Spreng.

Global description

Nelsonia canescens is a prostrate species of which only the spike like inflorescences are erected. The leaves are simple and opposite. They are very large and long petiolate at the base of the plant, on the other hand they are short, subsessile and woolly on the flowering branches. The flowers, protected by the bracts of the spike, are blue. The fruit is a dehiscent capsule containing many seeds.

Cotyledons

The cotyledons are briefly petiolate. They are oval to lanceolate, 15 mm long and 6 mm wide.

First leaves

The first leaves are simple and opposite. They are long petiolate. The blade is oval to elliptical, finely pubescent on both sides.

General habit

Nelsonia canescens is prostrate. The plant is abundantly branched and develops as a patch on the soil surface, up to 50 cm in diameter. Only the inflorescences are erect.

Underground system

The root is a taproot.

Stem

The stem is cylindrical and solid. It is finely streaked longitudinally. During the vegetative period, the stem is finely pubescent. On the other hand, during the flowering period, the stem of the flowering branches is very strongly pubescent, covered with long silver hairs.

Leaf

The leaves are simple and opposite. At the base of the plant, during the vegetative period, they are borne by a petiole 3 to 5 cm long. The blade is oval to elliptical and can be up to 15 cm long and 3 to 5 cm wide. The apex is wedge or narrowly rounded and the base is attenuated in elongated corner along the petiole, the margin is slightly curvy. The blade is marked with 8 or 9 lateral veins. Both sides are very finely pubescent.
The leaves of the flowering twigs are much shorter. They are subsessile. The limb is triangular oval. It is 4 to 6 cm long and 2 to 3 cm wide. The margin is entire and both sides are densely pubescent to woolly, which gives them a silvery white color.

Inflorescence

The flowers are grouped in axillary spikes standing vertically and long pedunculated. These spikes are cylindrical and measure 2 to 10 cm high. They are composed of numerous oval, silver-pubescent bracts, 6 mm long and 5 mm wide. Each bract masks a flower of which only the top of the corolla is visible.

Flower

The flowers are formed of a calyx with 4 sepals lanceolate unequal and pubescent; the widest is often divided into two lobes at the top. The corolla is asymmetrical. The petals are welded into tube at the base and divided into two lips at the top. The upper lip is reduced. The lower lip is broad and divided into three lobes. The corolla is pink or blue. The stamens are two in number.

Fruit

The fruits are fusiform capsules dehiscent, 4 mm long and 2 mm wide. Each capsule is formed of two boxes each containing 6 to 8 seeds.

Seed

The seeds are round and very small. They measure 0.3 mm in diameter. Their tegument is covered with fine sinuous wrinkles. They are light brown in color.

https://www.gbif.org/fr/species/5415356