Talinum porphyreum M.Mend. & J.R.I.Wood

Mendoza F., J. & Wood, J.R.I. 2013. Taxonomic revision of Talinum (Talinaceae) in Bolivia with a note on the occurrence of Phemeranthus (Montiaceae). Kew Bulletin 68: 233. https://doi.org/10.1007/s12225-013-9454-0

Morphology General Habit

Erect, fleshy herb 0.4 – 0.7 m high; roots 2 – 3, thickened, arising from the central base, not napiform; main stem 1, fleshy, tuberous base reduced, unbranched or, if branched, only at the base

Morphology Leaves

Leaves in a basal rosette, rarely cauline and, if so, reduced; petioles 0.2 – 2 mm long; laminas fleshy, obovate to spathulate, (4 –) 5 – 8 (– 9) × (2.5 –) 4 – 5 (– 6) cm, apex obtuse to truncate on basal leaves, acute on upper stem leaves, base attenuate

Morphology Reproductive morphology Inflorescences

Inflorescence of dense to moderately dense terminal panicles, 25 – 40 (– 60) × 10 – 15 cm; flowers arranged in lateral cymes, borne on a short, straight, terete primary axis 2.2 – 3 (– 4) cm; cymes 3 – 4 times divided, the branches opposite, secondary axes terete, 0.8 – 2 (– 2.5) cm long; bracts and bracteoles reduced, triangular, 1 – 1.5 mm long; pedicels filiform, slightly swollen below flowers, 7 – 15 (– 20) mm long

Morphology Reproductive morphology Flowers

Flowers open at night from 18 to 06 hours, small, ± 0.5 cm diam., numerous, >50 per panicle; sepals 2, broadly ovate, 1 – 1.2 × 0.7 – 0.9 mm, subequal, caducous; petals obovate, 2 basal straight, 3 upper reflexed, yellow with a reddish tinge, apex concave-inflexed, obtuse; filaments 15 – 20, unequal; anthers elliptic, bright yellow; style shorter than the filaments, filiform, slightly widened at apex; stigma trifid

Morphology Reproductive morphology Fruits

Fruit a weakly 3-angled subglobose, 3-valved capsule, valves separate, rapidly caducous, intervalvular membrane present, caducous, but briefly held in place by the intervalvular filament; seeds (Fig. 1E) subglobose, 1 – 1.2 × 0.9 – 1 mm, black, the surface covered in robust papillae arranged in concentric lines with irregular pores between the papillae; caruncule reduced or absent, membranous, white-hyaline, caducous

Distribution

A chaco species known only from Bolivia and Paraguay. In Bolivia it is restricted to the department of Santa Cruz where it is found in Caballero and Vallegrande provinces between 1000 and 2000 m growing on open banks, field borders and roadsides in spiny bushland with the presence of cacti and Capparis spp. in the warm inter-Andean valleys with a strong chaco influence. In Paraguay it grows in dry chaco forest between 100 and 200 m on the plains of Amambay and Boquerón departments.

Conservation

Although it is easy to estimate the area of occupancy of this species based on the cited collections, no information is available on population sizes or on the level of threat they may face. Any classification within IUCN (2001) guidelines other than Data Deficient (DD) would be premature especially as this species, like Talinum nocturnum, extends into the poorly known areas of the Chaco between Bolivia and Paraguay.

Note

This species can be confused with Talinum paniculatum and to a lesser extent with T. nocturnum with which it shares a fleshy stem and leaves and a paniculate inflorescence with small flowers ± 0.5 cm in diam. T. porphyreum can be distinguished by the reddish-purple colour, which is a feature of all its parts and all stages of its growth, by the single, usually unbranched central stem (if branches present, basal only), the leaves in a basal rosette (rarely stem leaves present) and by 15 – 20 anthers per flower. In contrast T. paniculatum, is always green in colour, the single central stem is branched from the base, the stem leaves are relatively abundant and alternate almost from the base while each flower has only 10 – 12 anthers. T. nocturnum is also green in colour, but there is no central stem and 3 – 7 secondary stems arise from the base, the stem leaves are relatively abundant and alternate from the base, while each flower has only 8 – 10 anthers.

The specific epithet refers to the distinct reddish-purple colour of this species, which makes it a distinctive and easily recognisable plant.