70 



perfection in the Hawaiian Archipelago. Those species thrive 

 best that require subtropical rather than tropical, conditions. 

 The Cherimoya is the hardiest of the cultivated species, and 

 requires a comparatively cool climate for optimum development.* 

 The sour-sop, on the other hand, is very tender, and requires the 

 warmth of tropical lowlands. The other species of horticultural 

 importance are intermediate between these extremes. 



The Hawaiian Islands are remarkable, not only for the very 

 high endemicity of the indigenous flora, but also for the great 

 diversity of the introduced flora. Plants have been brought in 

 from all parts of the world, from the days of the first European 

 explorers, down to the present time. These first explorers were 

 Spaniards, and probably the earliest line of communication from 

 the outside world to Hawaii was from Mexico and Central 

 America, the home of many Annonas. Hence it is not surprising 

 that the custard-apples became established in Hawaii at a 

 relatively early date. The Spaniard, Don Marin, who settled 

 in the islands near the close of the eighteenth century, was 

 actively interested in tropical horticulture, and introduced 

 many useful fruits and other plants. 



The four species abundant in the Hawaiian Islands are A. 

 miiricata, cheromolia, reticulata, and squamosa. These are the 

 forms most generally cultivated in other parts of the tropics. 

 The genus Annona is characterized by two-ranked often pungent- 

 aromatic, alternate leaves, without stipules; blade entire, 

 leathery, and often punctate. The flowers are perfect; solitary 

 or in clusters; rarely racemose; extra-axillary, often opposite the 

 leaves, and sometimes subterminal; nodding. The calyx is 

 usually gamosepalous, three-parted, deciduous. The petals are 

 typically six, in two series; the outer valvate, fleshy, concave, 

 converging, three-angled at the apex; in some species the inner 

 series is reduced to small scales, or wholly lacking. Stamens 

 numerous, crowded on the hemispheric receptacle; the filament 

 is fleshy, and bears a pair of linear, parallel, contiguous anthers* 

 united on its back; the anthers open extrorsely by a longitudinal 



* See F. W. Popenoe, The Cherimoya in California, Journ. Econ. Bot. Pomona 

 College, Vol. 2, 1912, pp. 277-300. 



