FIG. 10 in Lygodium hians E.Fournier (Pteridophyta, Schizaeales) - an endemic unusual groundclothing member of a modern climbing fern genus in New Caledonia

FIG. 10. — Scenario for the predominance of the climbing frondform of Lygodium Sw., developing from a basic dichotomous structure. A, a theoretical initial stage in which a series of simple sequenced dichotomies form a successive set in which left and right branches become alternatively indefinitely developed; B, the shorter branches of each non-continuing dichotomy are each soon 'stopped' from further indefinite development by establishment of a non-continuing terminal bud, but with a lateral 'pinna' pair of definite growth forming a pseudo-dichotomy; C, the typical frond-form in most modern Lygodium species in which each noncontinuing dichotomous branch and its arresting bud are eventually reduced to nothing. Paired 'pinnae' only remain, and these may bear further sets of foliage in successive complex 'pinna' arrangement developments in individual species.