HISTORICAL BIOGEOGRAPHY OF CHARA (CHAROPHYTA): AN APPRAISAL OF THE BRAUN‐WOOD CLASSIFICATION PLUS A FALSIFIABLE ALTERNATIVE FOR FUTURE CONSIDERATION1

Abstract

ABSTRACTTo that classification of the genus Chara, first advanced by Braun in 1847 with subsequent reiteration by the same author in 1867 and 1882 and by Wood in 1962 and 1965, an alternative is here proposed. Contended strengths of the present model include: i) a more accurate reflection of the phylogeny of the genus; ii) conformity with current distribution of dioecious taxa assumed consistently ancestral to their monoecious, morphological counterparts; iii) assumption of allopatric speciation primarily as a result of tectonic movement; and, iv) a foundation of underlying conjecture nearly all of which is potentially falsifiable in the Popperian sense as well as predictive with respect to a wide array of features. Deemphasized or rejected are previous assumptions that; i) stipulode, and to a lesser extent cortical, development reflect major evolutionary trends; ii) endemism is rare in the Charophyta; iii) dioecism and monoecism can be accommodated infraspecifically; iv) evolutionarily significant transitions between the preceding occur in both directions; v) hybridization contributed significantly to the phylogeny of the Charophyta; vi) section Grovesia is monophyletic in origin; and, vii) the Chara flora of Australasia arrived via India. The evidence upon which this classification rests is considered primarily with respect to the genus Chara, although the model appears equally applicable to the genus Nitella.