The plant is single stem with spiral leaves at the top. It grows up to 10 meters height depending on the specie. The drawing below by Koeh depicts the details.
Strangely it shows a forked tree. That is rather rare at least in Kerala, India, where I come from. The ripe fruit is absolutely delicious. It is an anytime table fruit. The skin which is normally greenish to golden yellow and the seeds are removed and the flesh is cut into pieces. Another way to eat it is to cut the fruit into boats with the skin on, clear the seeds and scoop out the flesh with a spoon. This is a favorite breakfast food.
Green papaya is used for cooking in many countries particularly for salads, stews and curries. In Kerala there is papaya thoran (sautéed with grated coconut), curry with ground coconut or buttermilk, kofta curry in which grated papaya is shaped into small balls and cooked in spicy gravy. My mouth waters when I think of papaya halwa that my grandmother used to make. (See Gold color chips and a golden hearted Lady )
One could write pages about the medicinal properties of papaya. Here is a sample list: aphrodisiac, excellent source of vitamin A & C, improves digestion, useful in high blood pressure management, good for heart health, effective in treating skin disorders and fungal infections. The list goes on. For details you can visit http://www.whfoods.com/genpage.php?tname=foodspice&dbid=47
Papaya, especially the skin of the raw fruit has latex which contains an enzyme known as papain. It is available in the shops for use as meat tenderizer and for helping digestion. It is also said to have contraceptive properties and to induce abortion. Pregnant ladies are, it seems, advised to keep off papaya.
The photo below from Olavipe shows a male papaya tree with flowers. The male tree also has fruits but they don’t grow big enough to be served ripe on table. The larger ones among them can be used for cooking.
Top – AK Kepler, believed to be public domain
Center – Wikimedia Commons Public Domain
Bottom – Abraham Tharakan. Can be used freely for non-commercial purposes giving due credit.