Monographs Details: Cyathodium foetidissimum Schiffn.
Authority: Bischler, Hélène, et al. 2005. Marchantiidae. Fl. Neotrop. Monogr. 97: 1--262. (Published by NYBG Press)
Description:Species Description - Thallus light green, delicate, elongate, dichotomously branched, 4-17 mm long, 1-6 mm wide; marginal cells chlorophyllose, quadrate to short-rectangular, oil cells triangular. Dorsal epidermis delicate, without trigones, chlorophyllose, cells (15-) 20-37.5 µm long, (15-) 18-30 µm wide, oil cells smaller, 15 µm long, 19-23 µm wide, with a single, hyaline to grayish oil body. Epidermal pores simple, smaller toward apex, surrounded by 3-4 irregular rows of elongate cells, these with minute chloroplasts. Ventral epidermis chlorophyllose, chloroplasts smaller than those of dorsal epidermis, cells polygonal, larger than those of upper epidermis 75-160 µm long, (24-)33-68(-75) µm wide. Midrib (= central multistratose area) present. Rhizoids abundant, long, and colorless, of 2 types, narrow and strongly tuberculate, or wide and smooth, basal rhizoid area brownish. Ventral scales large, multicellular, long-rectangular to irregularly deltoid, 4-7 cells wide, 7-8(-12) cells long, with oil cells in idioblasts. Monoecious. Antheridial receptacles sessile in apical sinus, cushion-shaped, oval to oblong, flanked on both sides by archegonia. Archegonia on both sides of male receptacle, enclosed by sinuous laminar involucre. Sporophytes with a short seta, 0.6-0.8 mm in diam., dark brown, operculum of 12 cells, projecting into the capsule cavity; cells in upper 1/2-1/3 of capsule, below operculum, with tangential bar thickenings, lowermost cells smooth. Spores dark brown, subtriangular in shape, verrucose-tuberculate 31-42 |im in longest diam, (not including verrucae). Elaters 390-600 µm long, 12-15 µm wide, with 3 thickened bands, attenuated at apex.

Discussion:The 2 collections examined are the only records of this species from tropical America. In general aspect, sterile thalli of this species closely resemble small or young thalli of Cyathodium spruceanum. The presence of a multistratose central area ("midrib"), oil bodies in specialized idioblasts, strongly tuberculate rhizoids, and the inner row of cells surrounding pores not abutting into the opening, separate C. foetidissimum from C. spruceanum. Fertile plants are distinctly different in the involucral morphology and sexual condition. Cyathodium steerei is dioecious, with a saccate involucre opening by 2 apical lips, whereas C. foetidissimum is monoecious and has involucres that are laminar and occur on both sides of the apically located male receptacle. Other species having oil bodies in idioblasts are C. cavemarum and C. bischlerianum, but the latter 2 species grow in rosettes or produce very minute thalli without midrib. Also, when fertile, these 2 species produce their male receptacles laterally, unlike C. foetidissimum, which produces them apically.

Distribution and Ecology: Cyathodium foetidissimum is widespread in the Old World tropics and had not previously been reported from the Neotropics. This species has recently been collected in Costa Rica and Ecuador. In Costa Rica the species was found growing at 1150 m elevation in small patches in depressions on a sandy limestone rock wall hidden by vascular vegetation, in very shady conditions, next to Dumortiera hirsuta (Sw.) Nees and Marchantia sp., and mixed with Fissidens flaccidus Mitt., Taxiphyllum taxirameum (Mitt.) Fleisch., and a species of Lejeuneaceae. A collection from Ecuador (150 m elevation), identified by Srivastava as Cyathodium cf. foetidissimum, has strongly tuberculate rhizoids typical of C. foetidissimum but the uppermost thallus cells are larger than in the material from Costa Rica. In addition, the specimen from Ecuador has vegetative tubers, which are unknown in C. foetidissimum. Probably this Asiatic species is more widely distributed in the Neotropics; the scarcity of collections may be due to the small size and delicacy of the thallus.

Distribution:Cartago Costa Rica Central America| Los Ríos Ecuador South America|