Today’s photo shows a leaf of Begonia paulensis. Also known as spider web begonia, these large, ribbed leaves resemble spider webs. The leaves account for only a part of this species’ intriguing morphology!
Begonias are considered to be almost every plant in the family Begoniaceae. The Begoniaceae contains around 1500 species from only two genera, Begonia (all of the begonias) and the monotypic (i.e., with only one species in the genus) Hillebrandia. The diverse set of floral and leaf colours make Begonia extremely popular cultivated plants throughout the world. Although this pictured spider web begonia is cultivated and an exception, Begonia paulensis is relatively rare in cultivation and not commonly available for purchase. Due to the tropical and subtropical distribution of begonias, temperate growers need to cultivate them indoors or with ample protection from harsh weather (in milder temperate climates).
Native to southeastern Brazil, Begonia paulensis was first discovered in 1859 by Alphonse De Candolle near Sao Paolo. The specific epithet gives credit to its origin, as “paul” refers to Sao Paolo and the Latin suffix “ensis” means to “originate from”.
Begonia paulensis is a relatively short-growing and rhizomatous species. Young leaves first emerge blushing-red in colour, but the red fades with age. Though appearing to have a glossy surface in today’s photograph, leaves typically bear small hairs on both upper and lower surfaces. Orbicular in shape when young and turning roughly ovoid as they grow, the leaves can reach up to around 25 cm (10 in.) in length. Photographs of the flowers are difficult to find, as plants don’t seem to flower much (or at all) in cultivation. The small white flowers have remarkable petals, each one covered on the back by small red spikes. Two pictures of these flowers on a plant in the wild by gjshepherd_br@Flickr (photo 1 and photo 2) seem to be the only ones available online. These odd, spike-like protrusions from the petals look similar to the soft hairs that coat the leaves and stem. Resemblances have been drawn from the appearance of the flowers with Venus fly-traps, sea urchins, and hedgehogs! An account of spider web begonia by Paul Tsamtsis goes into further detail and provides some good insights on its cultivation.