Diplazium
|
Diplazium  |
|
|
Family: Woodsiaceae  |
Greek diplazios, double, alluding to the "doubling" of sori often seen in this genus where they are found on both sides of the veins. Plants medium-sized to large, terrestrial. Rhizomes creeping to erect. Stipes adaxially grooved; cross sections at bases reveal ends of 2 ribbon-shaped vascular bundles (appearing as linear and parallel lines) that unite forming a single U-shaped bundle in upper stipes. Blades 1- to 4-pinnate, apexes pinnatifid; rachises glabrous, adaxially grooved, grooves continuous with grooves of pinna costae, no spinelike appendages at bases of costae and costules in Hawaiian species. Veins free, simple, forked, or uniting below sinuses to form veins excurrent to sinuses. Sori medial, usually linear, single or doubled, nearly always doubled and on both sides oflargest basal vein branch. Indusia linear, attached along lengths of sori. A worldwide genus of about 400 species. Represented in Hawai 'i by three endemic and one naturalized species, as well as a widespread hybrid continuum between two endemic species. KEY TO THE SPECIES OF DIPLAZIUM IN HAWAI'l 1. Veins arising pinnately from costae, lower 2-4 branches joining to form zigzag excurrent veins to sinuses; ultimate segments large, 3-8 x 0.5-2 cm; sori arranged in "herringbone" pattern; plants of streamsides and swampy soil. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. D. esculentum 1. Veins free; ultimate segments or lobes much smaller; sori not arranged in "herringbone" pattern; plants of mesic to wet forests (2). 2(1). Blades lanceolate-oblong, up to 55 em long, 1-pinnate to 1-pinnatepinnatifid; sori often very long, up to 1.3 em long, curved; all major islands except Hawai 'i. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. D. molokaiense 2. Blades deltate-ovate to ovate or deltate-elongate, up to 1.5 m long, 2- pinnate-pinnatifid to 3-pinnate-pinnatisect; sori 3-6 mm long, not curved (3). 3(2). Sori 1-3 mm long, mostly submedial; blades medium to light green, thin-chartaceous; veins not prominent; ultimate segments 4-6 mm wide, narrowly oblong, usually close; all major islands ......................................... 4. D. sandwichianum 3. Sori 3-6+ mm long, extending nearly to margins; blades dark green, thickchartaceous; veins prominent; ultimate segments 6-8 mm wide, oblongdeltate, usually remote; all major islands ..................... 1. D. arnottii |
