Identification and structure
Tacinga armata is an accepted species described in 2021. Plants reach 30–80 cm tall and retain an upright habit. The dark green, oblong segments are 5–15 cm long, 3,5–5,5 cm wide and 0,6–1,3 cm thick. Compared with the similar T. palmadora, its stronger armature and spines on the pericarpel and young fruits are conspicuous. [Freitas et al. 2021] [2-WWW]
An areole can produce 6–15 spines. The radial spines, usually numbering 5–12, are 1–4,5 cm long, while one to three central spines reach 1,5–5,5 cm. Young spines are golden. Older ones turn white while retaining brown tips. Small leaves, 0,5–0,8 cm long, are a transient feature of young growth and fall off quickly. [Freitas et al. 2021]
Flowers, fruits and reproduction
The red flowers are 3,5–4 cm long and 1,5–2,5 cm wide. Eighteen tepals form three series, and the stigma usually has six lobes. The young, oblong fruit retains one to five spines per areole. As it ripens, it becomes rounded, reaches about 3 cm and changes from dark green to pinkish. The spines may then fall off. [Freitas et al. 2021]
The translucent pulp contains reddish fibres. Counts of 48–52 seeds were recorded in the described fruits, including underdeveloped seeds. Mature fruits remain on the plant for a long time and can produce new shoots after falling. This observation documents a pathway of vegetative propagation. The reported total seed count does not indicate the proportion capable of germination. [Freitas et al. 2021]
In field material, flowers were observed in December and January, and in September. In the collection they also appeared in other months, while fruit ripening took at least four months. These timings describe the plants studied in Brazil and their growing conditions. [Freitas et al. 2021]
Distribution and cytology
The protologue documents five populations from the Borborema Plateau in Paraíba and Pernambuco. They grew at elevations of 700–1100 m, on granite outcrops and shallow, compacted soils, usually in full sun. At Serra da Bolandeira, the species occurred alongside T. palmadora. The current POWO list confirms a range covering both states. [Freitas et al. 2021] [2-WWW]
Meristematic cells had 2n = 66 chromosomes, corresponding to hexaploidy at x = 11. The combination of cytological data, stem and fruit armature, and a distinct set of floral characters formed the basis for recognising the species. The authors drew attention to small, scattered populations and the transformation of their habitats. [Freitas et al. 2021]