Today's entry was written by Alexis:
This photo was provided by Anne Elliott (annkelliott@Flickr). Spotted in the Calgary Zoo in Alberta, Anne notes that the flowers of this dwarf cultivar of Calliandra haematocephala measured only "maybe an inch across." Thanks, Anne!
Though it is widely cultivated, Calliandra haematocephala is native only to Bolivia. Calliandra haematocephala is a shrub or tree species that can grow to 6m in height and plants produce pink flowers with long red stamens measuring about 3 cm arranged in dense heads. This results in the flower's intriguing appearance and the plant's appropriate common name, red powder puff (see: Phillips and Rix's Indoor and Greenhouse Plants from 1997). Photoperiod plays an important role for the species, as Calliandra haematocephala flowers mostly bloom in the winter months when there are fewer hours of daylight (noted in Barwick's Tropical and Subtropical Trees (2004)).
Pictured in today's photo is a dwarf cultivar, either of the species or possibly a hybrid between Calliandra haematocephala and Calliandra surinamensis, a similar-looking species known as pink powder puff (http://toptropicals.com/cgi-bin/garden_catalog/cat.cgi?uid=Calliandra_nana). Dwarf incarnations of Calliandra haematocephala are also popular for bonsai.