Senna surattensis
Common name: Glaucous Cassia, Scrambled Egg Tree, Golden Senna, Singapore Shower, Sunshine Tree, Sulphur-flowered senna •
Marathi: Motha farvad •
Kannada: Adavi tangadi, Bettadavare,
Glaucous Cassia is a small tree and very common in Southeast Asian gardens
and is also often seen planted along citystreets and roadsites. The
flowering days of Galucous Cassia are prolonged and beautiful. As a
species, it is capable of flowering from January through December. Many
trees have their best show in the spring and summer while others are
at their showiest from fall into spring. The trunk and branches are
a silver-gray color. The bright,sometimes pale yellow flowers appear
continuously at the end of the branches. Flowers are very similar to
those of Indian Laburnum, but never look so spectacular because they do
not hang in bunches. Flowers attract butterflies. It is a rapidly easy
growing tree,which tolerates poor soil.
Many trees have their best show in the spring and summer while others are at their showiest from fall into spring. Late summer and mid winter are usually the two periods of minimum or no flower displays, and mid winter is when many trees can become quite unkempt.
What’s quite noticeable is that most
trees, growing in close proximity to each other, either put on an exceptional show or nary a flower. This suggests that flowering is stimulated by local maintenance regimes more so than by changing weather. Newly planted trees must be kept well watered to become established and apparently to flower adequately.
After establishment reduce irrigation. In alternate years, prune once after a major flowering episode to keep a tight attractive canopy. You may want to prune more often since heavy flowering can leave some trees disheveled, with scant leaves and dry,hanging, blackened pods. The trunk and branches are a silver-gray color. The crown is naturally rounded and airy, but pruning and wind damage will thicken and shorten the canopy of many trees. Easily toppled by wind,S. surattensis should probably be staked for up to three years after planting or until it becomes properly established.It is generally not a long lived tree,and will usually not survive for more than 6 years under normal street scape conditions. However, properly tended, it can live for more than 10 years. This means keeping it properly standing and maintaining it free of scales and the pink hibiscus mealy bug. Typical of this genus,S. surattensis attracts egg-laying cloudless sulfur butterflies. The caterpillars feed on the leaves and flowers of the tree. However, caterpillar feeding does little to detract from the beauty of its magnificent displays. Maintain a fertilizer schedule for best appearance.
Senna species make good ornamental plants and are used for landscape gardening. The wide variety of species and ecological adaptations makes at least a handful of sennas suitable for any climate warmer than cool-temperate.
Cassia gum - a commonly-used thickening agent - despite its name, is actually from Chinese Senna (S. obtusifolia) seeds.
In some Southeast Asian cuisines (particularly those of Thailand and Laos), the leaves and flowers of Siamese Senna (S. siamea, called khi-lek in Thai), either fresh or pickled in brine, are used in cooking, particularly in gaeng khi-lek (khi-lek curry).
Another senna, Senna italica ssp. italica (= Cassia obovata), often called "neutral henna", is used as a hair treatment with effects similar to henna
but without the red color.
The active component is an anthraquinone
derivative called chrysophanic
acid(1,8-Dihydroxy-3-methylanthraquinone), also called chrysophanol,
which is also found in higher concentrations in
rhubarb root. It adds a slight yellow color. Chrysophanol has been reported to have antimicrobial and anti-inflammatory properties. It is also used by the beetle
Galeruca tanaceti as a pheromone
.
Some species of
Senna are notable for being host to
caterpillars of certain
Lepidoptera species, for example
The sennas are typically
shrubs or
subshrubs, some becoming
scandent when growing into other vegetation. Some are
herbs or small
trees. Many species have
extrafloral nectaries.
The
leaves are
paripinnately compound, the
leaflets opposite. The
inflorescence is a
raceme, or some arrangement or racemes. The
pedicels lack
bracteoles.
The
flowers produce no
nectar. They are
buzz pollinated and offer
pollen as a reward to
pollinators. They are often asymmetric. The
petals are 5 in number, similar to each other,
yellow, or rarely
white.
The
stamens may be as few as 4, but usually there are 10. When 10, they occur in 3
sets. The 3
adaxial stamens are
staminodial. The 4 medial stamens are smaller than the 3
abaxial stamens. The
anthers are
basifixed and
open by two terminal pores or short slits.
The
gynoecium is often
enantiostylous; that is, it is deflected laterally to the right or left. This makes the flower asymmetric, but the
perianth and the
androecium may be asymmetrical as well.
The
fruit is a
legume,
indehiscent or tardily dehiscent.