The flowers grow in clusters from the bases of the leaf stems. The flowers are unisexual, but both male and female flowers are produced on the same plant. (Wagner 1990)

Best germination is obtained with fresh, mature seed. Remove the seed from the fruit flesh. Discard any seeds that have insect damage or that float in water.

Bornhorst says that scarification is not required to improve germination. However, Lilleeng-Rosenberger recommends scarifying the seeds using a clippers, file or sandpaper, or cracking them with a hammer being careful not to damage the end where the seed will sprout. Some of Stratton's survey respondents recommended scarification using a file followed by soaking in hot water for 1 hour or tepid water for 24 hours.

Koebele recommends the following procedure for treating seeds of Sapindus oahuensis. The seeds should be scarified with a clippers or a knife. Following scarification, the seeds can either be kept in clean, moist verimulite for 1 or 2 weeks, or be soaked in a shallow pan of water until the dark outer seed coat is soft. If the seeds are soaked, the water should be changed daily. Once the outer coat has softened, it can be removed by hand or with a small knife and then the thin papery brown inner coat should be carefully peeled off. This procedure leaves the cream colored embryo exposed. Handle the embryo carefully so that the embryonic root is not damaged. The embryo should be planted immediately in sterile potting soil, burying it 3/8 to 3/4 inch deep. With this method, Koebele has found that germination takes place in about a week and the germination rate is almost 100%. Germination of untreated seeds or of seeds which have only been scarified takes 1 to 6 months and the germination rate is variable since the seeds tend to rot.

Some of Stratton's respondents also recommended removal removing all of the seed coats and using the embryo for propagation. They recommended a planting the prepared seeds in a shallow container using a fast draining, sterile medium such as a mixture of 3 parts #2 perlite to 1 part Sunshine Mix #4. The medium should be kept moist and the container put in a shaded area until germination. Placing the container under cover will allow better control of soil moisture and prevent rain damage.

Cleaned, air dried seeds can be stored in a paper bag or envelope placed inside an airtight container with desiccant. They should be kept in a cool place at 25% relative humidity. (Bornhorst 1996; Culliney 1999; Koebele 1998; Stratton 1998; Wagner 1990)

Culliney, John L., and Bruce P. Koebele. 1999. A native Hawaiian garden: how to grow and care for island plants. Honolulu: University of Hawai'i Press. p. 53-55.

Koebele, Bruce P. 1998. A highly effective method for germinating aulu/lonomea (Sapindus oahuensis). Newsletter of the Hawaiian Botanical Society 37 (3):46.

Lilleeng-Rosenberger, Kerin. 1998. Propagation techniques for native Hawaiian plants. Newsletter of the Hawaiian Botanical Society 37 (2):33-35.

Stratton, Lisa, Leslie Hudson, Nova Suenaga, and Barrie Morgan. 1998. Overview of Hawaiian dry forest propagation techniques. Newsletter of the Hawaiian Botanical Society 37 (2):13, 15-27.

Wagner, Warren L., Darrel R. Herbst, and S. H. Sohmer. 1990. Manual of the flowering plants of Hawai'i. 2 vols, Bishop Museum Special Publication 83. Honolulu: University of Hawaii Press and Bishop Museum Press. p. 1229.