From the legumes of arizona project:
an illustration of dalbergia sissoo, the indian rosewood

While we’re all eagerly anticipating the 2019 publication of the long-awaited Legumes of Arizona: An Illustrated Flora and Reference, we will continue our periodic look at some of the book’s illustrations. Here is a drawing of Dalbergia sissoo, the Indian rosewood, by Tucson artist Chris Bondante. Note that because this tree is not native to the Sonoran Desert, Chris’s illustration is not included in the Sonoran Desert Florilegium.

Dalbergia sissoo, also known as sissoo or sisham, is native to plains, low hills, and mountain valleys of the sub-Himalayan region and has been introduced in many dry climates of the world, becoming naturalized in Africa, Australia, and the United States. Growing to 60’, the tree’s wide green canopy provides welcome shade, and it has been used widely in tea plantations as a windbreak as well as a shade tree. Its fast growth rate and extensive root system are useful in erosion control, but prolific suckers can create a problem with invasiveness (in Florida, it has been classified as an invasive exotic). In India, the brown heartwood of sissoo is second only to teak in value as high quality timber. Like other non-native trees that grow well in Tucson, sissoo thrives in our alkaline soil and is drought tolerant.

Chris’s illustration of Dalbergia sissoo shows the habit of the plant (at left), a flowering branch with compound leaves, each with 3-5 leaflets. These leaves are pubescent when young, becoming leathery with age. The small flowers at top right form a panicle, or cluster, that can also be seen in the habit. Flowers are yellowish-white and slightly fragrant. An enlarged flower below this cluster illustrates the butterfly-like form typical of the legume subfamily Papilionoideae (see Desert Breeze June 2018). Directly beneath the flower is the arrangement of 9 stamens (male) surrounding the pistil (female). To the left of the reproductive structures is the fruit, a flattened pod with intricate venation that can contain 1-4 seeds.

The genus Dalbergia was first described by Carl Linnaeus the younger, in Supplementum Plantarum (1782), a work of botanical descriptions by the elder Linnaeus with additions by the son. The genus was named to honor the Swedish brothers Carl Gustav Dalberg (1721-1781) and Nicolas Dalberg (1736-1820), both of whom had connections with Linnaeus. Carl Dalberg was a Swedish mercenary in the Dutch colony of Surinam who became, through marriage, one of the wealthiest men in the colony. He returned to Sweden twice with large collections of nature specimens that were given to the King of Sweden and to Linnaeus. Nicolas Dalberg studied medicine in Uppsala University where he also studied with Linnaeus. He traveled throughout Europe with the King of Sweden, making numerous connections in the scientific community. He was twice elected president of the Swedish Academy of Sciences.

If you want to see Indian rosewood up close, the University of Arizona campus is a good place to find them. The Campus Arboretum’s website has a list of the sissoos planted there, complete with a handy map for locating each one in their collection (there are a number of them just east of the Tree Ring Research Laboratory). — Cindy Hartwell



This article appeared in the February 2019 issue of Desert Breeze, the monthly newsletter of the Tucson Cactus and Succulent Society.