Note 151 — Chapter III · HETEROTAXY.
Reading edition
Rœper, 'Enum. Euphorb.,' p. 19. Bernhardi, 'Linnæa,' vii, p. 561, tab. xiv, f. 1. Wydler, "Subcotyled. sprossbildung," 'Flora,' 1850, p. 337. Hooker, 'Trans. Linn. Soc.,' vol. xxiv, p. 20 (Welwitschia).