The Gametophytes of the Victorian Blechnaceae. II. Doodia aspera R. Br., D. media R. Br., and D. caudata R. Br.: A comparison with three extra-Australian Genera, Brainea, Sadleria, and Woodwardia

Abstract

An account is given of the spores, germination, and vegetative and reproductive features of the gametophytes of eight species of Blechnaceae. The close resemblance between the prothalli of Doodia aspera, D. media, and D. caudata and those of three Woodwardia species, Sadleria cyatheoides, and Brainea insignis is described. Minor differences in morphological and developmental features of the gametophytes were noted between all species but these were no greater between genera than they were between individual species of a genus.

Unlike Blechnum nudum, but like many other Blechnum species and other higher ferns the cordate prothalli bore unicellular papillate hairs. There was no evidence that the terminal cell of the primary filament ended in a hair or became quiescent with subsequent development of the wedge-shaped meristematic cell from a subterminal cell, a feature reported by others to be common in some species of Blechnaceae. The meristematic cell almost invariably appeared to be a product of the terminal cell of the filament although there was considerable variation in the sequence of divisions contributing to plate formation.

The antheridia were normally of the advanced type with three wall cells and showed similar variations in shape to those of B. nudum. Abnormal development of hairs on the wall cells of antheridia and the neck cells of archegonia is reported for the Doodia species. Various concepts concerning development of the cap cell of the antheridium are discussed. Antheridia were induced in W. japonica and were formed on prothalli of two or three cells, occasionally on the basal cell itself.

No archegonia were formed on prothalli of W. martinezii and this species was apogamous. Other species formed normal sporophytes. Juvenile leaves on young sporophytes of W. orientalis were slow to develop a dissected lamina, and pinnate venation and costal areolae were initiated before this occurred. In the Doodia species, however, early dissection of the blade occurred and no anastomoses between veins were observed on juvenile fronds with several pinnae.