Syrrhopodon helicophyllus Mitt.
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Description
Description: Plants yellowish-green above, glossy brown below, sometimes matted with dark-red rhizoids in older portions; stems to ca. 3 cm tall, infrequently branched, often repent and rhizome-like. Leaves when dry with upper lamina usually remarkably helically coiled and spreading-erect, with lower lamina appressed to stem, plane and erect when wet, 3-4 mm long, 0.5 mm wide at shoulders; upper lamina 3 times length of lower, linear to gradually tapering, contracted abruptly to acute, rarely denticulate apex, cells thick-walled, porose, pellucid, square to rectangular, mostly 12 X 36 micromenters, smooth and flat dorsally, slightly bulging ventrally; lower lamina widest at shoulders, only slightly wider than upper lammina, cancellinae persistent, tapering to costa above, sharply distinct; costa smooth on both surfaces, percurrent, cross section showing no enlarged epidermal cells, with stereids and single row of guide cells; leaf margins entire all around, uniformly bordered by a thick band of elongated hyaline cells to or nearly to apex, composed entirely of stereids as seem in cross-section; propagula filamentous, septate, to ca. 160 micrometers long, produced dorsally and ventrally along the costa on old, brown lower leaves; perigonia not seen; perichaetia terminal, leaves little differentiated although reduced in size, mostly bearing 2-3 sporophytes. Capsule erect; operculum slenderly rostrate, 1.4 mm, red; urn cylindric, yellow, 1.5 mm, a few stomata on upper portion of hypophysis; peristome ca. 145 micrometers tall, fairly well developed, teeth slender, articulated, vertically striated on outer surface; spores 17 micrometers, granular, seta red, 4 mm; calyptra 2-2.2 mm, slightly roughened above.
Discussion: The large, smooth, porose cells of the upper lamina are diagnostic. Helically coiled leaves often occur in several other species of Syrrhopodon, S. elongatus,S. gaudichaudii and S. prolifer var. cincinnatus, for example. The propagula are exactly like those of S. parasiticus, but their production on both the dorsal and ventral surfaces of the leaf is, to my knowledge, unique in Syrrhopodon. The fact that they are formed only on older leaves, well below the green upper portion of the stem is also of interest. A consequence of this method of producing propagula would seem to be that escape of dehisced propagular from the mat would be difficult or even unlikely.
Ecology and distribution: In dense springy mats, mostly on tree trunks but occasionally on soil, at low elevations (to 200 m). Endemic to northern Amazonas, Brazil and adjacent Colombia
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Floras and Monographs
Syrrhopodon helicophyllus Mitt.: [Article] Reese, William D. 1993. Calymperaceae. Fl. Neotrop. Monogr. 58: 1-102.
