55 (November/December 1998)
Spotlight on: Begonia angularis
by Mary Weinberg
In 1820 Guiseppe Raddi, an Italian botanist, published 40 species that he had collected in Brazil. B. angularis was on this list.
B. angularis Raddi is cane-like, tall growing, over 4 feet at maturity. It is a glabrous plant of medium strength, more or less bushy, ornamental by virtue of its leaves. Stems are erect, slightly branched, hexagonal roundish angled, red in color and brown at the base, with long internodes and a deep red ring at the base. Leaves are medium, ovate oblong, cordate, acuminate, undulate-crenate, denticulate on the edges, glabrous, thick; the upper surface is dark green with silky lights and marked with silver bands along the primary veins; underneath is pale green on a red ground. Stipules are large, ovate-lanceolate, pale green quickly turning brown, persistent. Many very small white flowers appear on long erect peduncles. Male flowers have four tepals, female five. It is a sparse bloomer; in four years, my plant has never bloomed.
Physical Characteristics of Brazil
Brazil is a vast country, consisting of hilly upland plateaus and low mountains. Coastal plains are not extensive. In the north, Brazil has the world's most extensive tropical rain forest. The rain forest area has been so deeply leached during long exposure to heavy rainfall that it has little sustained fertility for shallow rooted plants. The central part of the country is the Amazon Basin. The soil in this area is alluvial, sand and clay deposited by flowing waters; very little of this area is subject to floods. The south consists of forests and tall-grass prairie. The central- west land is hilly with torrential streams.
Rainfall varies throughout the country, from an annual average of 40 inches in the south to over 80 inches in the north and northwest.
Temperatures in January average between 68-86 degrees in most of the country. In July the north averages 68-86 degrees and the south 50-68 degrees.
Light: B. angularis enjoys a semi-sunny location. Morning sun is ideal, and the plant can take some afternoon if it is not too hot.
Temperature: B. angularis is most happy with a temperature range between 65 and 75 degrees, but can take cooler temperatures of 40-50 degrees with no apparent harm.
Humidity: B. angularis does not require a high humidity, and gets along fine on a windowsill or shelf. In taking cuttings, I usually place a plastic bag over the cutting to help the plant promote roots. The last cutting I removed from the bad to pot had long hairy roots formed at all the nodes above the submerged base of the cutting.
Propagation: B. angularis roots easily from stem cuttings. This is the fastest way to get a full pot.
Growing medium: This plant does not appear to be fussy about the type of mix used, possibly due to the fact that Brazil does not seem to have very rich soil. I have been using the suggested soil mix in the Thompson's Begonias: The Complete Reference Guide, and my B. angularis seems to be very happy with it. Whatever you use, make sure it is a porous mix.
Potting: I have B. angularis in a clay pot. I think clay is best for all cane-like begonias, with the exception of hanging plants.
In 1937 the New York Botanical Garden received a plant from Kew Gardens labeled B. acutangularis. After studying the plant they changed its name to B. acutangula. Bessie Buxton thought this plant was a seedling of B. angularis. Chevalier a few years later designated it as B. angularis, Raddi var. alta Hort. Leod. It is a much larger plant than B. angularis, reaching eight feet at maturity. To this day it is considered a hybrid of B. angularis.
Daniel Haseltine points out that B. angularis often has been called by other names, such as B. zebrina. In 1820 Dr. Edgar Irmscher established B. acutangula and B. zebrina as synonymous to B. angularis Raddi. A sport of B. angularis listed in an old catalog was called B. acute angularis.