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Squamidium (Müll. Hal.) Broth. 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: Die Natürlichen Pflanzenfamilien 1((3)): 807. 1906. (Nat. Pflanzenfam.) Name publication detailView in Biodiversity Heritage Library
 

Project Name Data (Last Modified On 10/3/2009)
Acceptance : Accepted
Project Data     (Last Modified On 4/29/2013)
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Notes     (Last Modified On 4/29/2013)
Notes:

Squamidium contains seven species distributed in subtropical and tropical America and Africa; all seven species present in the Neotropics; all restricted the montane forests. The genus is characterized by the pendent or occasionally spreading or creeping habit, short to long acuminate or piliferous, deeply concave, smooth, ovate to oblong-ovate leaves, distally incurved, smooth to finely serrate margins, slender single costa, smooth linear laminal cells, and well defined alar region. Gametophytically, quite variable with regard to growth forms, resulting in a considerable number of previously described species. Traditionally Squamidium was placed in the Meteoriaceae, and recently in the Lembophyllaceae. Allen and Crosby (1986) have provided a detail treatment with excellent illustrations of Squamidium. Keys provided here are adopted from the same source.
 
Squamidium contiene siete especies distribuidas en América y áfrica tropical y subtropical; las siete especies están presentes en el Neotrópico; todas restringidas a bosque montano. Este género se caracteriza por su hábito pendiente u ocasionalmente patente o reptante, hojas corto- a largo-acuminadas o pilíferas, profundamente cóncavas, lisas, ovadas hasta oblongo-ovadas, distalmente incurvadas, márgenes lisos hasta finamente serrados, costa delgada simple, células de la lámina lineales y lisas, región alar bien definida. Gametofito, bastante variable respecto a su forma de crecimiento, resultando en un número considerable de especies previamente descritas. Tradicionalmente Squamidium fue ubicada en Meteoriaceae y recientemente en Lembophyllaceae. Allen y Crosby (1986) brindaron un tratamiento taxonómico detallado con excelentes ilustraciones de Squamidium. Las claves ofrecidas aquí fueron adaptadas de la misma fuente.


 

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Plants medium sized to somewhat large, forming mats or pendulous strands, glossy green, yellowish-green or golden-brown, portions often black or blue sheen. Primary stems creeping or pendent, leaves broadly ovate-piliferous, base short long decurrent. Secondary stems spreading to more often pendent; in cross-section outer 3-5 rows of cells small, thick-walled, inner cells larger, thin-walled, central strand weak; paraphyllia and pseudoparaphyllia absent; rhizoids clustered beneath prostrate stems, reddish-brown, smooth. Leaves narrowly to broadly ovate, deeply concave, apex short to long acuminate or piliferous, base weakly auriculate and decurrent or not; margins plane below, distally usually incurved, smooth or serrulate distally; costae 3/4-4/5 lamina length, weak; apical cells short or long rhomboidal; median cells linear, often flexuose; insertion cells elongate, strongly porose, often golden-yellow or -brown; alar region differentiated, cells somewhat inflated and oval or quadrate, usually porose. Filiform stems present or not, slender; leaves lanceolate- or oblong-lanceolate-piliferous; margins entire to distally coarsely toothed, teeth often sharply recurved. Dioicous. Perichaetia lateral; leaves differentiated. Setae shorter or somewhat longer than capsule, rather stout, smooth. Capsules immersed to short exserted, ovoid-cylindrical; exothecial cells rectangular, rather thick-walled; stomata at base of urn; annuli in several rows, deciduous; opercula rostrate; peristome double, exostome teeth 16, narrow, papillose or smooth below; endostome often shorter than exostome, lightly to densely papillose, basal membrane ± high, segments 16, linear, variously perforate, cilia absent or rudimentary. Calyptrae mitrate, often hairy. Spores spherical, lightly papillose.

 

Plantas medianas hasta algo grandes, formando matas o cordones péndulos, de color verde brillante, verde-amarillento o pardo-dorado, con porciones a menudo negras o azul lustrosas. Tallos primarios reptantes o pendientes, hojas anchamente ovado-pilíferas, base corta largo-decurrente. Tallos secundarios patentes hasta más a menudo pendientes; en corte transversal 3-5 filas externas de células pequeñas con paredes gruesas, células internas mayores con paredes delgadas, cordón central débil; paráfilos y pseudoparáfilos ausentes; rizoides agregados entre los tallos postrados, pardo-rojizos, lisos. Hojas angostas hasta anchamente ovadas, profundamente cóncavas, ápices corto- hasta largo-acuminado o pilíferos, bases débilmente auriculadas y decurrentes o no; márgenes planos hacia la base, por lo general distalmente incurvados, lisos o serrulados distalmente; costa ocupando 3/4-4/5 de la longitud de la lámina, débil; células apicales corto- o largo-rómbicas; células mediales lineales, a menudo flexuosas; células de la inserción alargadas, marcadamente porosas, a menudo amarillo-doradas o -pardas; región alar diferenciada, células algo infladas y ovales o cuadradas, generalmente porosas. Tallos filiformes presentes o no, delgados; hojas lanceolado- u oblongo-lanceolado-pilíferas; márgenes enteros hasta gruesamente dentados en la porción distal, dientes a menudo claramente recurvados. Dioicas. Periquecios laterales; hojas diferenciadas. Setas cortas o algo más largas que las cápsulas, bastante robustas y lisas. Cápsulas inmersas hasta corto-excertas, ovoide-cilíndricas; células exoteciales rectangulares con paredes muy gruesas; estomas en la base de la urna; anillo en varias filas, deciduo; opérculo rostrado; peristoma doble, exostoma con 16 dientes, angostos, papilosos o lisos hacia abajo; endostoma a menudo más corto que el exostoma, ligera a densamente papiloso, membrana basal ± alta, 16 segmentos, lineales, diversamente perforados, cilios ausentes o rudimentarios. Caliptra mitrada, a menudo pelosa. Esporas esféricas, finamente papilosas.

 

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Keys adapted from Allen and Crosby (1986).

 

1. Secondary stems and branches with a short to long piliferous tip … 2.

1. Secondary stems and branches acute or acuminate … 3.

2. Alar cells rectangular to square, thin-walled, excavate, confined to area at leaf insertions, not extending up the margins; upper laminal cells usually porose; branch leaves loosely erect to more or less spreading; leaf base cordate … S. leucotrichum

2. Alar cells quadrate to oblate, firm-walled, extending up the margins; upper laminal cells not porose; branch leaves erect to imbricate; leaf base not cordate … S. brasiliense

3. Alar cells confined to area of stem attachment, not extending to margin, leaf margin smooth, rarely denticulate; leaf base cordate … S. livens

3. Alar cells extending from area of stem attachment to margin, leaf margin serrulate distally; leaf base not cordate … 4.

4. Branch leaves tightly erect, alar cells quadrate to oblate, firm-walled ... 5.

4. Branch leaves loosely erect, alar cells shortly rectangular, to quadrate, usually lax … 6.

5. Apices of stolon leaves with recurved teeth extending onto leaf shoulders; branch leaves acute to acuminate… S. diversicoma

5. Apices of stolon leaves entire or weakly serrulate, teeth not recurved; branch leaves long to short acuminate … S. brasiliense

6. Stem leaves short-acuminate; branch leaves serrate distally, margins broadly incurved distally, usually meeting below an apiculate to shortly acuminate, recurved apex; apex not galeate … S. nigricans

6. Stem leaves hair-pointed; branch leaves entire or weakly serrulate distally, margins erect, slightly recurved, apex broadly acute to short acuminate, frequently galeate ... 7.

7. Stolon leaves with strongly recurved marginal teeth extending from leaf apex to leaf shoulders … S. macrocarpum

7. Stolon leaves entire or with a few short marginal teeth on leaf apex, if present the teeth neither recurved nor extending onto the leaf shoulders … S. isocladum

 

 

 
 
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