DICROGLOSSUM CRISPATULUM GEN ET COMB-NOV FROM WESTERN-AUSTRALIA, REPRESENTING A NEW TRIBE WITHIN THE DELESSERIACEAE (RHODOPHYTA)

Dicroglossum gen. nov. (Delesseriaceae, Ceramiales) is a monotypic gen us based on Delesseria crispatula, a species originally described by H arvey for plants collected from southwestern Western Australia. Distin ctive features of the new genus include exogenous indeterminate branch es; growth by means of a single transversely dividing, apical cell; ab sence of intercalary divisions In the primary, secondary, and tertiary cell rows; lateral pericentral cells not transversely divided; not al l cells of the secondary cell rows producing tertiary cells rows; all tertiary initials reaching the thallus margin; midrib present but late ral nerves absent; determinate lateral bladelets arising endogenously; blades monostromatic, except at the midrib, carpogonial branches rest ricted to primary cell rows, on both surfaces of unmodified blades; pr ocarps produced on both blade surfaces, each procarp consisting of a s upporting cell that bears two four-celled carpogonial branches and one sterile-cell group of three to four cells; and tetrasporangia borne i n two layers, separated by a central row of sterile cells. The combina tion of exogenous indeterminate branching and bicarpogonial procarps i s considered to warrant the recognition of a new tribe, the Dicrogloss eae, within the subfamily Delesserioideae.