Carica papaya L.

Dioecious or occasionally polygamous or monoecious trees 2-8 m. tall with characteristic stout succulent and unbranched trunks, usually glabrous in all parts or essentially so. Leaves in a dense terminal crown, long-petiolate; blade simple but palmately divided into usually 7 more or less irregularly and broadly pinnatifid segments, variable in size but frequently up to 4-5 dm. in diameter; petiole usually up to 5-7 dm. long. Staminate inflorescences repeatedly compound, many-flowered, somewhat shorter than the subtending petioles, spreading or pendulous, the pistillate far shorter than the subtending petioles, usually only 1-to 3-flowered. Staminate flowers: calyx lobes very broadly deltoid, obtuse, about 1 mm. long; corolla salver-form white or yellow, the tube about 1.5-2.0 cm. long, about 2 mm. in diameter, the lobes oblong, 1.0-1.5 cm. long, slightly spreading; stamens inserted at the orifice of the corolla tube, exserted, the antepetalous anthers about 2.5 mm. long, nearly sessile and descending basally into the corolla tube, the antesepalous anthers erect, wholly exserted, about 2 mm. long, with apically 2-lobed filaments of nearly equal length; pistillode acicular, about 1 cm. long. Pistillate flowers far larger than the staminate, irregularly campanulate, white or pale cream: calyx lobes broadly deltoid, about 1 mm. long; corolla essentially polypetalous or very weakly united, the segments about 5-7 cm. long, 1.5-2.0 cm. broad, broadly acute, irregu-larly reflexed toward the tips; staminodia lacking, rarely minute and hypogynous; ovary ovoid-ellipsoid, usually about 3 cm. long (including the indefinitely attenuate style) and 2 cm. broad, the stigma essentially sessile, of 5 thick segments about 1 cm. long fimbriately di-or trichotomous toward the tip. Berry extremely variable, up to 3 dm. long and 2 dm. thick, green or yellow when ripe.

It is a tropical plant. Pawpaws will grow from sea level up to about 1700 m altitude in the equatorial tropics. In cooler regions they have to be planted but in humid tropical regions are commonly self sown. Sunlight allows germination when forest is cleared. Plants cannot stand frost. A temperature of 25-30°C is suitable. They need a night temperature above 12°C. Also they cannot stand water-logging. Plants die after 48 hours in standing water. It needs a pH between 5-8. It suits hardiness zones 11-12. In XTBG Yunnan.

Fruit can be eaten ripe and raw. Green fruit can be cooked as a vegetable. The young leaves can be eaten cooked, but are bitter. The flowers and the middle of the stem can be eaten. Papayas contain papain which is a meat tenderiser. The dried seeds can be used as a spice.

Pawpaw seeds grow easily and plants grow quickly. Fresh seeds can be used, or if dry seeds are used they should be soaked before planting. Seeds should be planted with a temperature of 24-30°C. To produce well they need a reasonably fertile soil. Seeds can be sown directly or the seeds can be put in a nursery and the seedlings transplanted. Seeds in a nursery should be about 1-2 cm deep. Seedlings can be transplanted when they are about 20 cm high. Plants should be about 3 m apart. Continuous fruit production depends on fertility, temperature and moisture being adequate to maintain active growth. The fruit is produced year round but the growth and development rate decreases with temperature. Also the size and quality of fruit declines at lower temperatures. Pollination is by wind and insects. Normally cross and self pollination both occur. Pollination is not normally limiting. Seeds are widely dispersed by birds, bats and people. Seeds remain viable for a few months and also germinate freely.