Of the total number of species found globally, Nepal possesses 2.80 percent plants. Record from 2006 shows that Nepal has 6,391 flowering plant species, representing 1,590 genera and 231 families. Nepal’s share of flowering plant species is 2.76 percent of the global total compared to earlier records of 2.36 percent. Nepal’s share of pteriodophytes is 5.15 percent compared to earlier records of 4.45 percent.
There are 2,532 species of vascular plants represented by 1,034 genera and 199 families in the protected sites. Some 130 endemic species are found in the protected sites.

For ecology and vegetation purpose Nepal could be divided into four floristic regions i.e.
(a) western
(b) north-western
(c) central, and
(d) eastern, and bio-climatically these are broken down into twenty regions from humid tropical climate to the arid, alpine regions.

There are 399 endemic flowering plants in Nepal of which about 63 percent are from the high mountains, 38 percent from the mid hills, and only 5 percent from the Terai and Siwaliks. Similarly, the central region contains 66 percent of the total endemic species followed by 32 percent in the western and 29 percent in the eastern regions.

Medicinal Plants:
The Himalayas are famous for medicinal plants and have even been mentioned in the Aurveda. Many of the herbs and plants found in the Himlayas are used in traditional healing systems like Ayurvedic, Homoeopathic, Amchi etc. Some of these plants are even used for allopathic medicine. Medicinal plants are abundantly found in: the Terai region of Nawalparasi, Chitwan, Bardia, Dhanusha, mid hill region of Makhwanpur, Syangja, Kaski, Lamgjung, Dolakha, Parvat, Ilam, Ramechhap, Nuwakot, and the Himalayan region of Dolpa, Mugu, Humla, Jumla, Manang, Mustang and Solukhumbu.

Orchids:
In ancient Rome, Theophrastus, a student of Plato, was intrigued by the sight of a plant with a pair of roots. Orchis was the name he gave them, the Greek word for testicles. Worldwide, there are some 500 to 600 genera and some 20,000 to 35,000 names, the largest of all plant families, and out of this, Nepal has 57 genera (27 Terrestrials and 30 Epiphytic) with a few Lithophytes.Nepal is endowed with an incredible variety of orchids scattered across the country. Dedrobium is the largest species, followed by Habenaria and Bulbophyllum. Anthogonium, Hemipilia and Lusia are some of the other varieties amongst the nearly two dozen single species families.

Source: welcomenepal.com