A Peculiar New Species of Trichomanes sect. Selenodesmium and Several of Its Probable Hybrids

Abstract

On December 27, 1965 a peculiar species of Trichomanes, first thought to be in the sect. Davalliopsis, was collected in New Caledonia. It proved to be the first species of Trichomanes sect. Selenodesmium that has leaf blades more than one cell thick. The relatively exposed habitat (altitude ca. 300 m along the trail from the Dumbea Dam to Montagne des Sources) which, however, seemed to be supplied with subsurface water, correlates with the nearly sclerophyllous fronds of the new species. Substratum samples unfortunately yielded no hymenophyllaceous gametophytes, only thallose ones identified as Blechnum sp. and filamentous ones clearly belonging to Schizaea fistulosa. Bierhorst NC460 included two mature specimens, and Bierhorst NC465 included one sterile, halfgrown plant with associated substratum. The material was preserved in a chromic acid-acetic acid-formaldehyde solution in the field and was later transferred to glycerine alcohol. Type material will be dried and deposited in the Gray Herbarium, Harvard University. Freehand sections of all parts of the plant were prepared and stained with 1% Methyl Green for 5 min followed by two rinses in water. The sections illustrated in Figs. 11 and 13-18 were prepared in this manner. The cleared leaf shown in Figs. 4 and 20-22 was bleached in Clorox until white (ca. 15 min; monostromaticous species generally take 1-3 min), rinsed with three changes of water, dehydrated in 70%, 95%, and 100% ethanol (5 min each). It was then stained with Fast Green (1% in 100% ethanol) for 3-5 min, rinsed in two changes of 100% ethanol (total ca. 5 min), then one change of 1:1 xylene-absolute ethanol, then cleared in xylene (two changes of 5 min each), and finally mounted in synthetic resin HSR. The new species is designated: