The different habitat types of Corbett i.e. mountains, sal forests, chaurs, khair-sissoo forests, and rivers have their distinct assemblage of plants. More than 600 species of trees, shrubs, herbs, bamboos, grasses, climbers and ferns have been identified in the Park.
The most visible trees found in Corbett are sal, khair and sissoo (see Habitats and Ecosystems). Many other species that contribute to the diversity, are found scattered throughout the park.
Chir pine (Pinus roxburghi) is the only conifer of the Park and is found on ridge-tops like Chir Choti but comes quite low in Gajar Sot. The upper reaches near Kanda have Banj Oak (Quercus leucotrichophora) growing which is essentially a Himalayan species.
Palms include Khajur or Date-palm (Phoenix sp.) that occurs in open areas. Wallachia densiflora is a rare palm characteristic of Eastern Himalayas but is found in Corbett near Sultan.
Kanju (Holoptelia integrifolia), Jamun (Syzygium cumini) and Aamla (Emblica officinalis) are found scattered throughout the lower areas while Tendu (Diospyros tomentosa) occurs in moist areas. Other major tree species are Bel (Aegle marmalos), Kusum (Schleichera oleosa), Mahua (Madhuca indica) and Bakli (Anogeissus latifolia).
Flowering trees lend colour to the forests in Corbett. The main ones are Kachnaar (Bauhinia variegata) with pink to white flowers, Semal (Bombax ceiba) with big red blooms, Dhak or Flame-of-the-forest (Butea monosperma) with bright orange flowers, Madaar or Indian Coral (Erythrinia indica) with scarlet red flowers and Amaltas (Cassia fistula) with bright yellow chandelier like blooms.
Some species of trees that do not occur naturally in the Park have been artificially planted in and around habitation. These include Teak (Tectona grandis), Eucalyptus, Jacaranda (Jacaranda mimosaefolia), Silver Oak (Gravillea robusta) and Bottlebrush (Callistemon viminalis), and can be seen in and around forest rest houses.
Shrubs dominate the tree understorey and scrub areas. There are several species of Ber (Zizyphus sp.) in open areas and provide food and habitat to many birds and animals. Maror phali (Helicteres isora) is an easily noticeable shrub. Its fruits are in the form of twisted spiralling pods. Karaunda (Carissa sp.), with pinkish-white flowers and sour fruit, is found under sal. Hisar (Rubus ellipticus) has yellow, juicy, mulberry-like fruits that are savoured by animals.
Jhau (Tamarix dioica) is found along the Ramganga basin on sandy or rocky soil. Colebrookia oppsitifolia and Adhatoda vasica are found in nallahs.
In some parts of Corbett the vegetation is dominated by bamboo forest. The main species is Male Bamboo (Dendrocalamus strictus) having clustered stout stems and shining papery stem sheaths.
Bamboos follow a peculiar flowering process. All bamboos in a forest flower together at the same time once in several decades. After flowering, fruiting and dispersal of seeds, all individuals die together.
Herbs include many species of wildflowers belonging mostly to Pea and Aster families. They are most visible on grasslands or chaurs and on open areas.
Drymaria diandra is a spreading annual herb with heart shaped leaves and occurs in moist shady places. Bhilmora (Rumex hastatus) is a sour tasting herb used for making chutney. Other species encountered in Corbett are Euphorbia hirta, a hairy herb, Indigofera liniofolia with bright red flowers, Clover (Oxalis sp.) with three leaflets, Solanum sp. and Leonotis nepatafolia (orange flowers and spiky round fruits).
Grasses form the largest group of plant species in Corbett with more than 70 species recorded. They occupy different habitats, especially chaurs.
They include Kansi (Saccharum sp.), Themeda arundinacea, Baib or Bhabar (Eulaliopsis binata), Narkul (Arundo donax), Tiger Grass (Thysanolaena maxima), Khus Khus (Vetiveria zizanioides), Cymbopogon flexuosus (a tufted grass with pleasant aromatic leaves), Aristida cyanantha (found amidst boulders), Neyraudia arundinacea (with light brown inflorescence) and Heteropagon contortus (Spear Grass with conspicuous sharp blades that adhere to clothes and penetrates skin).
Woody climbers found in the park are Milletia auriculata, Crypotepris buchanani, Porana paniculata (dense canopy with profuse white flowers), Clematis gouriana (shrubby twiner with tendril like branches) and Bauhinia vahlii (flat rusty hairy pods, large leaves used for making pattal)
Epiphytes and orchids
Epiphytes are plants that grow above the ground on other plants, and derive nutrients and water from rain, the air, dust, etc. They are found on sal and other trees in the park.
They include Dendrophthoe falcata (scarlet red flowers), Scurrula cordifolia (hairy coating on shoots and leaves), Vanda testacea (orchid with flat keeled leaves and beautiful spike flowers), Cuscuta reflexa (or ‘Dodder’, with interlaced yellow cord like habit, growing on shrubs).
The semi aquatic species which inhabit marshy areas of Corbett include Polygonum, Veronica, Hypericum and Ranunculus etc.
Non-flowering plants include ferns, mosses and lichens. Ferns occur in cool shady moist areas along streams. They include Adiantum, Pteris, Ophioglossum reticulatum (Snake-tongued Fern which occurs below Sal), Equisetum (found growing on sandbanks along streams). Many kinds of fungi are found on rotting trunks and accumulating debris. These include mushrooms, brilliantly patterned toadstools, and puffballs. The presence of lichens symbolises good air and environment and many kinds of colourful lichens grow on mature tree trunks and boulders all over Corbett. Liverworts and mosses are found on moist trunks.