The Flora of Ranganathittu Bird Sanctuary
By K.B. Sadananda
1. Thorny Scrub jungle in the central part of the islands where desert conditions prevail
Among the plants, the flowering ones take the pride of place both in number and variety of species. There are 400 species of dicotyledonous plants belonging to 79 families. Of these the family Fabaceae (Leguminosae) with 69 species stands first. The families Astteraceae (Compositae) and Euphorbiaceae, with 28 species each, stand second and the family Acanthaceae with 20 species takes the thirds place. The monocotyledonous plants belong to 114 species distributed among 14 families. Poaceae (Graminae) with 55 species and Cyperaceae with 27 species stand first and second among the monocotyledons.
The scrubby vegetation is made up of thorny plants such as Capparis sp., Dichrostachys cinerea, Pterolobium hexapetalum, Flacourtia indica, Plecospermum spinosum, Zizyphus sp., Toddalia asiatica, and Acacia sp. There are also plants like Dodonaea viscosa, Cassia auriculata, Hardwickia binata, Maytenus emarginata, Grewia tiliaefolia which show xerophytic features. The bushes and trees are festooned with several types of climbers such as Ichnocarpus frutescens, Gymnema syslverstre, Cassytha Filiformis, Cocculus hirsutus, Cissampelos pareira, Passiflora foetida, Cissus quadrangularis, the leafless Sarcostemma intermedium and others.
Special mention must be made of interesting new find from this area-Iphigenia mysorensis belonging to Liliaceae. This is an entirely new species described for the first time in 1972.
Other plants of interest that are found here include Hydrocotyle conferta (Apiaceae) which appears to be a new addition to the flora of Karnataka and Heliotropium subulatus (Boraginanceae) which looks like Oldenlandia of Rubiaceae.
The alluvium rich marginal areas of the islands and riverine harbour broad leaved trees like Syzigium cumini, Barringtonia racemosa, Terminalia arjuna, Vitex leucoxylon, Commiphora caudata, Bauhinia racemosa, Samanea saman, Ailanthus exccelsa, Holptelea intergrifolia, Pithecellobium dulce, Albizia amara, etc.
Pandanus fascicularis (Screwpine) is a very common plant and forms impenetrable thickets along the water margins. It is interspersed with Combretum albidum, Crateva magna, Caesalpinia bonduc and Acacia sinuata.
There are many Aegle marmelos, Limonia acidissima, Atalantia monophylla, Salix tetrasperma, Guazuma ulmifolia, Phoenix syslvestris sparingly distributed in edges of river edges. While the openground is covered with different types of grasses, succulents like Bryophyllum, Kalanchoe, Caralluma, Opuntia, grow under the bushes and trees. Fig: Crateva magna
The marshy inlets which are periodically flooded with watter harbour plants such as Cryptocoryne retrospiralis, Alterrnanthera sessilis, Centella asiatica, Eclipta alba, Spilanthes calva, Aeschynomene aspera, Enicostemma hyssopifoliuum, Portulaca oleracea, Pouzolzia pentandra, Scoparia dulcis, Ammannia sp., Polygonum sp., Rotala sp., Commelina sp., etc.
Fig: Pistia stratiotes Fig:Rotala rotundifolia
Several species of medicinal plants are also seen in the sanctuary. The most notable ones are Hemidesmus indicus, Asparagus racemosus, Trichodesma indicum, Hybanthus ennespermus, Evolvulus alsinoides, Tinospora cordifolia, trianthema portulacastrum, Alangium salvifolium, Gymnema sylvestre, Acalypha indica, Phyllanthus fraternus, Tephrosia purpurea, Boerhavia diffusa, Bacopa monnieri, Scilla hyacinthiana and Cynodon dactylon.
The marsh plants include Hydrilla verticillata, Ottelia alismoides, Vallisneria spiralis, Lemna perpusilla, Najas graminea. The riverbank is covered with Crinum defixum and several types of sedge's.
The non-angiospermous plants are few in numbers. But still one can see a rare and curious plant called Horsetail Fern (Equisetum ramosissimum) belonging to Equisetaceae. It grows under the Bamboo clumps and along the bunds of the adjoining paddy fields. Other common ferns are Pteris sp., Azolla pinnata and Marsilea minuta which favor marshy areas. Bryophytes such a Riccia sp., and Funaria sp., are also seen.
Fig: Mallotus philippensis