Monographs Details: Cyathodium spruceanum Prosk.
Authority: Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press)
Family:Targioniaceae
Description:Species Description - Thallus light green to greenish yellow, elongate, dichotomously branched, in large to discrete patches, 13-20 mm long, 1.5-8.0 mm wide, variable in size; marginal cells hyaline or with few chloroplasts and oil bodies, in 1-2 rows, turning brown with age. Dorsal epidermis delicate, cells at midthallus (25-)34-60(-90) µm long, (18-)30-96 µm wide with chloroplasts and 4-6(-8) translucent to light-brown oil bodies, walls thin, lacking trigones, markedly distended on their inner (air chamber) side. Epidermal pores simple, in 2 rows, slightly raised above epidermal cells, widely opened, surrounded by 4-5 rows of narrow, botuliform cells, the uppermost abutting into pore. Ventral epidermis chlorophyllose, chloroplasts smaller than those of dorsal epidermis, cells hexagonal to polygonal, at midthallus (60-)75-127(-180) µm long, (25-)37-60(-70) µm wide. Midrib absent. Rhizoids brown at insertion, abundant, long, of 2 types, smooth and tuberculate, lightly sinuous with spiral twisting. Ventral scales variable in appearance and number of cells, near thallus apex, on ventral walls and inside of involucre, larger on ventral walls of involucre, without appendages, hyaline to slightly brown, elongate triangular, 5-10 cells long, with lateral and terminal cells containing oil bodies. Dioecious. Antheridial receptacles apical, sessile, oval, elliptical, transversely elongate, lobate to horseshoeshaped, 1.3-3.0 mm long, 0.4-1.5 mm wide, surrounded by a lamina of elongate cells that projects from thallus lobes, scale wider distally; receptacles turning brown when mature with more than 100 antheridial chambers flanked by 4-5 rows of elevated cells surrounding pore. Female plants similar to male ones. Involucre large, with 5-30 archegonia and sometimes with l(-2) inner scales, brown and truncate at apex; larger scales and rhizoids on its ventral surface, opening by 2 smooth to slightly dentate, ± recurved lips on its distal surface, the lips below thallus rim or the upper portion of involucre projecting outwardly beyond rim and funnel-shaped when containing 10-30 archegonia; outermost cells of involucral lips reddish brown, oval, square to rectangular with thickened inner tangential walls. Sporophytes l(-2) per involucre, seta delicate 2(-3) seriate, 6 cells long. Capsules dark brown to black when mature, operculum of 6-12(-13) cells, slightly projecting apically, upper cells of capsule with irregular thickenings on their radial and tangential walls. Spores dark brown, (30-)37-42(-55) µm diam., lamellate-reticulate, lamellae projecting from surface of spore and vertically striated, 2-5 µm high, 0.7-2.8 µm wide, distal face with reticulum forming closed areoles, opened on proximal face, with a transverse cingulum dividing the spore in 2 asymmetrical halves; cingulum with a central, linear row of gemmae and minute perforations. Elaters 20-80(-100) per capsule, 600-780 µm long, 16-19(-24) µm wide, trispiral at middle, bispiral at attenuated ends. Vegetative propagation by ventral tubers and branches; tubers variable in size, with rounded, imbricate lobes, ventral scales, and numerous rhizoids.

Discussion:Cyathodium spruceanum grows in medium-sized to large patches. The thallus is elongate, and its size varies depending on environmental conditions. The opaque appearance contrasts with the bright metallic-green, rosette-forming thalli of C. cavernarum and C. bischlerianum that grow in the same habitats. Spore ornamentation is also variable, some populations having high, well-developed lamellae arranged in regular areoles, whereas others, collected at the end of the rainy season, have low, cord-shaped, thickened lamellae and a loose, open reticulum. Ventral tubers seem to germinate while favorable conditions prevail and are abundant during the peak of the rainy season. New thalli have been observed growing at the onset of the dry season among populations that have started to die; pH of soil analyzed for 14 sites in Panama ranges from acidic to slightly alkaline (5.4-7.6).

Distribution:Coclé Panamá Central America| Los Santos Panama Central America| Panamá Panama Central America| Alajuela Costa Rica Central America|