Tylotus laqueatus Kraft, K.Y.Conkl. & A.R.Sherwood (2014, p. 21)

Tylotus laqueatus Kraft, K.Y.Conkl. & A.R.Sherwood (2014, p. 21)

This species is endemic to the Hawaiian Islands, based on very infrequent records made from Oahu and Maui. Fronds are regularly dichotomous to subdichotomous, of uniformly narrow widths and often hummocked and imbricating ( Fig. 1 k View Fig ), becoming broader and more irregularly contoured proximally ( Kraft et al. 2014, fig. 7, 9). Anchorage is by numerous scattered haptera at the bases ( Fig. 1 l View Fig ) and along the lengths ( Fig. 3 n View Fig , Kraft et al. 2014, fig. 11–17) of distal fronds. Cross sections are composed of compact pseudoparenchyma throughout the interior, bounded by a shallow, even cortex on both sides ( Fig. 2 h View Fig ). Occurring in the outer cortex are numbers of short, ‘glandular’ hairs ( Kraft et al. 2014, fig. 19–21). Tetrasporangia occur in irregularly rounded sori scattered along the dorsal lengths of fronds ( Fig. 3 n View Fig ), the tetrasporangia flush with the surface on relatively short parallel nemathecial filaments ( Fig. 3 o View Fig ), with relatively few buried at deeper levels ( Kraft et al. 2014, fig. 24). Spermatangia occur in shallow subcortical ampullae ( Kraft et al. 2014, fig. 25–27). Carpogonial branches are three-celled and infrequently encountered, although the carpogonium appears to be in proximity to the supporting cell ( Kraft et al. 2014, fig. 28). Early gonimoblast development and basal placentation ( Kraft et al. 2014, fig. 30), and deep invaginations of the leading carposporophyte edge ( Kraft et al. 2014, fig. 29) and short carposporangial filaments ( Kraft et al. 2014, fig. 34) appear to be very similar to those of T. obtusatus but a major difference is the implantation of some gonimoblasts of the former into the inner surface of the domed pericarp, where these reverse direction and also produce sporebearing filaments into the cystocarp chamber ( Kraft et al. 2014, fig. 29, 31, 32).