Pereskia nemorosa

Range and former names

The natural range includes southern Brazil, Paraguay, Uruguay and northeastern Argentina. POWO associates the species with the subtropical biome. Synonyms include Rhodocactus nemorosus, Pereskia amapola and Pereskia argentina. [2-WWW]

Identifying the plant and flower

The shrub usually reaches 3–5 m, exceptionally about 8 m. Leaves are most often more than twice as long as wide, usually 4–14 cm long and 2–6 cm wide. Their shape changes through the season and between shoot types. Narrow leaves alone do not justify distinguishing a separate variety. [Leuenberger 1986, Pereskia nemorosa description]

The pink flower is usually 4–7 cm in diameter, sometimes up to 9 cm. Long hairs arise from areoles on the outside of the flower-bearing part. In addition, curly hair-like elements occur between tepals and stamens, interpreted as staminodes, modified stamens. This second hairy zone helps distinguish the species from the similar Pereskia sacharosa. Fruits reach about 4–6 cm long, and seeds 4.5–5 mm. [Leuenberger 1986, Pereskia nemorosa description]

The monograph documents forest margins, scrub and secondary communities in wetter, partly seasonally leafless vegetation of southern South America. Flowers were recorded from October to March, fruits from November to April, and partial leaf shedding from May to August. The seasonal pattern differs from conditions in the dry Chaco. [Leuenberger 1986, Pereskia nemorosa description]

Pith, wood and stem epidermis

In the young shoots observed, Leuenberger described a large pith, a relatively weakly developed wood cylinder and a thin primary cortex. The epidermis lacked stomata, although the periderm, secondary covering tissue, developed late. This combination is an important exception to a simple link between late cork formation and stomatal presence. [Leuenberger 2008]

Branching near flowers

Long hairs were observed in areoles near flower bracts. Further lateral flowers could arise near the receptacle. The description indicates that the flower-bearing part retains features of a shoot axis whose areoles participate in further development. A mature flower-and-fruit cluster may therefore be more branched than the initial bud. [Leuenberger 2008]

Mixed material in collections

Leuenberger linked some Paraguayan plants distributed under FR 640 to Pereskia nemorosa, although other material under this number corresponded to P. sacharosa. For such specimens, retaining precise provenance information for the particular batch is useful. A historical numbered label should not automatically be equated with an unambiguous identification of the entire series. [Leuenberger 2008]