The botanical name of rice is Oryza sativa.
It belongs to the Kingdom Plantae.
It is a Tracheophyte of the  phylum Angiospermata.
It is a Monocotyledonous plant and a member of the Commelinids.
The Order of rice is called Poales.
It belongs to the Family Poaceae.
The Genus is called Oryza.

Species of rice and their botanical names 

Asian rice - Oryza sativa

The botanical name of Asia rice is Oryza saliva. 
This is the most commonly grown species of rice. 
Has two major subspecies: the sticky, short-grained japonica or sinica variety, and the nonsticky, long-grained indica rice  variety. 
Japonica rice varieties of are usually cultivated in dry fields, in temperate East Asia, upland areas of Southeast Asia, and high elevations in South Asia, while indica varieties are mainly lowland rices, grown mostly submerged, throughout tropical Asia. 
This Rice occurs in a variety of colors, including white , brown , black, purple , and red rices. Black rice (also known as purple rice) is a range of rice types, some of which are glutinous rice. 
An additional subspecies of O. sativa, which is broad-grained and thrives under tropical conditions, was identified based on morphology is known as tropical japonica. 

African Rice - Oryza glaberrima

The botanical name of African rice is Oryza glaberrima. This species of rice is mostly grown in Africa.
It is hardy, pest-resistant, low-labour, suited to a variety of African conditions, filling, and has a distinct nutty flavour. 
It is a tall rice plant, usually under 120 cm but up to five meters for floating varieties, which may also branch and root from higher stem nodes. 
Generally, African rice has small, pear-shaped grain, reddish bran and green to black hulls , straight, simply-branched
panicles , and short, rounded ligules . 

Oryza rufipogon

This third species of rice has distinctive partitions spread into South Asian, Chinese, New Guinean, Australian, and American forms. 

Oryza australiensis

wild rice grows in northern Australia.

Oryza barthii

wild rice grows in sub-Saharan Africa.

Oryza latifolia

wild rice in central and south America.

Oryza longistaminata  

Red wild rice in South Africa

Oryza meridionalis 

wild rice in Western Australia, Northern Queensland.

Oryza officinalis

wild rice in Sri Lanka.

Oryza punctata 

wild rice in central and north Africa.

Oryza rufipogon 

wild rice in north America named brownbeard or red rice.

Oryza nivara 

Indian wild rice.

Botanical description of rice

The rice plant is an annual grass and grows to about 120 centimetres (4 feet) in height. The leaves are long and flattened and are borne on hollow stems. It has a fibrous root system which is often broad and spreading. 
The rice stem known as culm is hollow and is made up of nodes and internodes. Each node bears a leaf and bud, which may grow into a shoot or tiller. Primary tillers grow out of the main culm.
Rice grain is the ripened ovary with lemma and palea firmly adhered to it. The lemma and palea with other smaller components from the hull are removed in shelling rice for consumption.
The inflorescence is made up of spikelets bearing flowers that produce the fruit, or grain. 
Varieties differ greatly in the length, shape, and weight of the panicle and the overall productivity of a given plant. This normally serves a great function in the botanical identifications.