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Macrocoma (Hornsch. ex Müll. Hal.) Grout Search in The Plant ListSearch in Index Nominum Genericorum (ING)Search in NYBG Virtual HerbariumSearch in JSTOR Plant ScienceSearch in SEINetSearch in African Plants Database at Geneva Botanical Garden Decrease font Increase font Restore font
 

Published In: The Bryologist 47(1): 4. 1944. (Bryologist) Name publication detail
 

Project Name Data (Last Modified On 10/7/2009)
Acceptance : Accepted
Project Data     (Last Modified On 5/16/2013)
General Reference:

Notes     (Last Modified On 5/16/2013)
Notes:
Macrocoma contains nine species rather widespread in the subtropics and tropics, extending into the temperate regions of both hemispheres (Vitt, 1980); six species in the Neotropics. Rather semi-dry open montane forest in the tropical Andes; epiphytic, rarely on rocks. The genus is distinguished by the slender, wiry habit, the intertwining stems, erect, imbricate, short ovate-lanceolate to lanceolate leaves, costa ending well below apex, similar upper and lower laminal cells smooth to weakly unipapillose, oblong juxtacostal cells, the mostly rudimentary single or double or absent peristome, and the smooth to weakly plicate calyptra.
 
Macrocoma contiene nueve especies distribuida muy ampliamente en los subtrópicos y trópicos, extendiéndose en regiones templadas de ambos hemisferios; seis especies en el Neotrópico. El género se distingue por presentar hábito delgado, alambrino, con tallos entrelazados, hojas cortas ovado-lanceoladas hasta lanceoladas, erectas, imbricadas, costa terminando bien abajo del ápice, células de la lámina superiores e inferiores similares lisas hasta débilmente unipapilosas, células yuxtacostales oblongas, peristoma generalmente rudimentario simple, doble o ausente y caliptra lisa hasta débilmente plegada.

 

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Plants rather small, forming mats, dark green or brown. Primary stems creeping, often inconspicuous. Secondary stems erect, slender and stiff, irregularly pinnately few branched; in cross-section outer 1-2 rows of cells small, thick-walled, inner cells larger, rather thick-walled, central strand absent. Leaves erect-appressed, rarely twisted when dry, erect-spreading to spreading when wet, short lanceolate to ovate-lanceolate, ca. 1 mm long, apex obtuse or acute to acuminate; margins plane, recurved below, entire to crenulate; costae single, strong below, projecting at back, ending below apex; median cells oblong-oval or quadrate-rounded, often obliquely arranged, thick-walled, smooth to bulging-mammillose or papillose; lower and basal cells elliptical-rounded, mammillose to mammillose-papillose; juxtacostal cells near base often oblong. Autoicous (gonioautoicous). Perichaetia terminal on short branches; leaves usually elongate. Setae elongate, smooth. Capsules erect, urn cylindrical, short to long 8-ribbed; exothecial cells mostly short, thick-walled; stomata at urn base, superficial; opercula conic short to long rostrate; peristome double, rudimentary as basal membrane and papillose, or teeth 16 and striate-papillose. Calyptrae mitrate-campanulate, smooth or weakly plicate, sparsely hairy. Spores spherical, lightly papillose.
 
Plantas bastante pequeñas, formando matas, verde oscuras o pardas. Tallos primarios reptantes, a menudo inconspicuos. Tallos secundarios erectos, delgados y rígidos, pocas ramificaciones irregularmente pinnadas; en corte transversal 1-2 filas de células externas pequeñas con paredes gruesas, células internas mayores con paredes muy gruesas, sin cordón central. Hojas erecto-adpresas, rara vez torcidas en seco, erecto-extendidas hasta patentes en húmedo, corto-lanceoladas hasta ovado-lanceoladas, ca. 1 mm de largo, ápices obtusos o agudos hasta acuminados; márgenes planos, recurvados en la base, enteros hasta crenulados; costa simple, fuerte abajo, proyectándose hacia atrás, terminando debajo el ápice; células mediales oblongo-ovales o cuadrado-redondeadas, a menudo dispuestas oblicuamente, paredes celulares gruesas, lisas hasta abultado-mamilosas o papilosas; células inferiores y basales elíptico-redondeadas, mamilosas hasta mamiloso-papilosas; células yuxtacostales cerca de la base a menudo oblongas. Autoicas (gonioautoicas). Periquecios terminales en ramas cortas; hojas generalmente alargadas. Setas alargadas, lisas. Cápsulas erectas, urna cilíndrica, 8-costillas cortas hasta largas, células exoteciales generalmente cortas, con paredes gruesas; estomas en la base de la urna, superficiales; opérculo cónico corto- hasta largo-rostrado; peristoma doble, rudimentario como la membrana basal y papiloso, o tiene 16 dientes estriado-papilosos. Caliptra mitrada-campanulada, lisa o débilmente plegada, esparcidamente pelosa. Esporas esféricas, finamente papilosas.
 

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Key adopted from Vitt (1973).

 

1. Upper leaf cells strongly bulging-mammillose …2.

1. Upper leaf cells smooth or only slightly bulging … 3.

2. Leaves lanceolate, apices acuminate to acute; capsules narrowly elliptic to cylindric-fusiform, smooth or lightly 8-plicate in upper half … M. basiliensis

2. Leaves oblong-lanceolate, apices sharply acute, often with a small apiculus; capsules ovate-elliptic, distinctly 8-plicate throughout… M. frigida

3. Leaf tips twisted, slenderly acuminate; cells of the acumen longer than broad … M. gastonyi

3. Leaf tips plane, not twisted, acute or obtuse; cells of the acumen rounded, as broad as long … 4.

4. Upper leaf cells constant in size from margin to costa; peristome consisting of 16 well-formed, exostome teeth papillose … M. orthotrichoides

4. Upper leaf cells becoming larger towards costa, smaller along margin; peristome consisting of two low, white, coarsely papillose membranes … M. tenuis subsp. sullivantii

 

 

 
 
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