19. Boykinia Nuttall, J. Acad. Nat. Sci. Philadelphia. 7: 113. 1834.
[For Samuel Boykin, 1786-1848, planter, physician, and naturalist of Milledgeville, Georgia]
Richard J. Gornall
Neoboykinia H. Hara; Therofon Rafinesque
Herbs, rhizomatous, not stoloniferous (± stoloniferous in B. intermedia). Flowering stems erect, leafy, 10-130 cm, densely stipitate-glandular and eglandular-pubescent. Leaves in basal rosette and cauline; cauline leaves similar to basal, gradually reduced distally to sessile bracts; stipules present; petiole densely stipitate-glandular; basal leaf blades reniform to reniform-orbiculate or cordate, shallowly lobed to deeply cleft, base cordate, ultimate margins crenate to serrate, apex acute or rounded, surfaces stipitate-glandular, adaxial surface grooved over veins; venation palmate. Inflorescences compound, dichasial cymes, terminal from terminal bud in rosette, branches (3-)5-20(-30)-flowered, bracteate. Flowers ± radially symmetric; hypanthium adnate 1/2-5/6 to ovary, free from ovary 0.7-3 mm, usually green, sometimes purple; sepals 5, green to purple; petals 5, white (sometimes with pink veins in B. richardsonii); nectary tissue encircling base of styles at junction of ovary and free hypanthium; stamens 5; filaments linear to subulate; (anthers apiculate or obtuse); ovary 2/3 to completely inferior, 2-locular, carpels connate proximally; placentation axile; styles 2; stigmas 2. Capsules 2-beaked. Seeds (ca. 50-500), usually black, (brown in B. richardsonii), ellipsoid, tuberculate (smooth in B. richardsonii). x = 7.
Species 7 (6 in the flora): North America, nw Mexico, e Asia (Japan).
The Japanese species is Boykinia lycoctonifolia (Maximovicz) Engler, which, based on its morphology, seems to be most closely related to B. aconitifolia.