Question: What plant containing single-seeded, blue-black drupes is part of the Manilkara zapota family? 

Context articles: Manilkara kauki
Manilkara zapota
Achyronychia
Manilkara pubicarpa
Maingaya
Sideroxylon celastrinum
Manilkara huberi
Sinowilsonia
Manilkara subsericea
Manilkara pleeana

Manilkara kauki is a plant in the subfamily Sapotoideae, and the tribe Sapoteae of the Sapotaceae family; and is the type species for the genus "Manilkara".
 It occurs in tropical Asia from Indo-China (Cambodia, Myanmar, Thailand and Vietnam) to Malesia (Indonesia, Malaysia and Papua New Guinea); and also in northern Queensland in Australia.
 In Java, the plant is called sawo kacik, and is associated with the royal Javanese ritual.
 Throughout the world it is known generally by the name caqui, but in Australia it is called wongi.
Manilkara zapota, commonly known as the sapodilla ( ), is a long-lived, evergreen tree native to southern Mexico, Central America and the Caribbean.
 An example natural occurrence is in coastal Yucatán in the Petenes mangroves ecoregion, where it is a subdominant plant species.
 It was introduced to the Philippines during Spanish colonization.
 It is grown in large quantities in Pakistan, India, Thailand, Malaysia, Cambodia, Indonesia, Bangladesh and Mexico.
Achyronychia is a monotypic genus of flowering plant containing the single species Achyronychia cooperi, which is known by the common names onyxflower and frost-mat.
 This plant is native to the Mojave and Sonoran Deserts of northern Mexico and the U.S. states of California, Nevada, Utah and Arizona.
 In California, it is known from San Diego, Imperial, Riverside, Los Angeles, San Bernardino and Inyo Counties.
 In Arizona, it occurs in Yuma, Mohave, Pima, Pinal and Maricopa Counties.
 It has also been reported from Washington County in Utah, and from Clark County, Nevada.
Manilkara pubicarpa is a species of plant in the Sapotaceae family.
 It is endemic to Guyana.
Maingaya is a monotypic genus of plant containing the sole species Maingaya malayana.
 It is a tree endemic to Peninsular Malaysia.
 It is threatened by habitat loss.
Sideroxylon celastrinum is a species of flowering plant in the sapodilla family, Sapotaceae, that is native to Texas and Florida in the United States south through Central America to northern Venezuela and Colombia in South America.
 Common names include saffron plum and coma.
 It is a spiny shrub or small tree that reaches a height of 2 - .
 The dark green leaves are alternate or fascicled at the nodes and oblanceolate to obovate.
 Greenish-white flowers are present from May to November and are followed by single-seeded, blue-black drupes.
Manilkara huberi also known as masaranduba, níspero, and sapotilla is a fruit bearing plant of the genus "Manilkara" belonging to the Sapotaceae family.
Sinowilsonia is a monotypic genus of plant containing the single species Sinowilsonia henryi.
 It is endemic to China.
 It is threatened by habitat loss.
Manilkara subsericea is a species of plant in the Sapotaceae family.
 It is endemic to Brazil, and threatened by habitat loss.
Manilkara pleeana (zapote de costa) is a species of plant in the Sapotaceae family.
 It is endemic to Puerto Rico.