The Florida dwarf pawpaws (A. incana, A. reticulata, A. longifolia, A. obovata, A. pygmaea, and A. tetramera).
These are shrubs, which range in height from very small (0.3 m) to moderate (1.5 m) to tall (4 m). They are only marginally hardy, to zone 9 (-2°C), and are primarily adapted to sandy soils in the warm wet maritime climate of peninsular Florida. The ranges of A. longifolia, A. incana, and A. pygmaea extend somewhat further north, into southern Georgia and Alabama. Pollinators are principally beetles (Scarabaeidae) (Norman and Clayton, 1986), possibly flies; pollinators are thought to vary according to flower color. Seed dispersers may be tortoises, raccoons, and opossums. In spite of being endemic with restricted ranges, they are mostly nonendangered. Asimina incana and A. reticulata are weedy, react favorably to human disturbance, and are increasing in number (Kral, 1960). Asimina obovata, although more restricted (north central Florida, particularly the Ocala National Forest) is apparently a stable population. Asimina tetramera, the species most restricted in habitat (old dune scrub vegetation along the east coast of south Florida) has been reduced to two or three sites where it numbers fewer than 200 stems (probably fewer clones since asexual propagation is common in Asimina). Ward (1982) lists it as an endangered species.
The manner of variability, similarity and divergence of traits between the 8 species is not such as leads to consistent species groupings. The flowering traits of color and odor and of flowering habit are the most disjunct and noncontinuous, and divide the species into 4 groups which reveal the differing degrees of affinity among them (Table 3). The descriptions in Table 3 are based on Kral's understanding of Asimina with only minor elaboration from the author's experience and collected data. For a more detailed description of the species, the reader should consult Kral (1960).
Within Asimina the genetic variation is considerable, as is seen in Table 3, with differences in habit, indumentum, leaves, flowering habit, flowers, fruits, seeds, hardiness, and site-soil preference. Specifically:
Habit ranges from that of a small tree, through intermediate sizes of shrubs, to the very small shrub. All species are reported to spread underground, via rootsuckers and/or rhizomes. Some are stoloniferous.
Indument of buds and young growth varies in density from heavy to sparse, and in color from whitish blonde through orange, red, and brown.
Leaves vary from 4 to 30 cm in length. Leaf texture varies from membranaceous to coriaceous. Leaf shape varies from obovate through oblong-oblanceolate to linear lanceolate. The edges of the leaves may be more or less revolute or not at all revolute. The leaf position varies from pendant to ascending second.
Flowering habits are of three distinct types: (1) flowers arising from lateral buds in the axils of the previous year's growth, (2) flowers arising from lateral buds in the axils of the current year's growth, and (3) in A. obovata, flowers arising from buds terminating the shoot growth of the current year.
Flowers occur as essentially two distinct morphs with a minimum of intergrading
586