Cratoneuron

• Authority

  Hedenäs, Lars. 2003. Amblystegiaceae. Fl. Neotrop. Monogr. 89: 1--107. (Published by NYBG Press)

• Family

  Amblystegiaceae

• Scientific Name

  Cratoneuron

• Type

  Type. Cratoneuron filicinum (Hedw.) Spruce. The name is derived from the Greek cratos, strong, and neuron, nerve, referring to the strong costa of the leaves.

• Synonyms

  Callialaria Ochyra, Cratoneuron filicinum (Hedw.) Spruce

• Description

  Genus Description - Plants medium-sized, rarely smaller; green, yellow green, or brown. Stem somewhat stiff; pinnately or irregularly branched in one plane, occasionally almost unbranched; central strand present; hyalodermis absent; pseudoparaphyllia foliose; paraphyllia present, lanceolate or ovate-lanceolate, numerous or few, sometimes absent; rhizoids smooth, usually strongly branched and often forming tomentum, inserted at or just below costa insertions; axillary hairs rare, when present weak, with 1-2 upper hyaline cells. Stem leaves erect to patent, straight or falcate (gradually curved), narrow- to broad-triangular or rounded-triangular to ovate, narrowing gradually to apex, not or hardly plicate, plane or slightly concave, decurrent; apex ± long-acuminate or acumen slightly set off from rest of leaf; margin slightly recurved near base, otherwise plane, denticulate or sometimes finely so almost throughout; costa strong, single, usually percurrent or excurrent, rarely ending in acumen some distance below leaf apex; median laminal cells elongate-hexagonal or short-rectangular to short-linear, rarely linear, unistratose, ± incrassate, eporose, smooth; alar cells differentiated, usually strongly inflated and hyaline (when old sometimes brownish), rectangular or sometimes short-rectangular; alar group large, transverse-triangular, reaching or nearly reaching costa. Branch leaves smaller and somewhat narrower than stem leaves, sometimes with shorter costa; proximal branch leaves broad and rounded, obtuse or apiculate. Dioicous. Perigonial leaves narrowing abruptly from broad base to acuminate or short-acuminate apex. Inner perichaetial leaves narrowing gradually or ± abruptly to acuminate apex, plicate; margin unbordered, denticulate in acumen, denticulate or strongly denticulate at shoulder; costa single, long, ending in acumen; vaginula with paraphyses. Calyptra naked. Seta long, red. Capsule cylindrical and curved throughout, horizontal; annulus separating; operculum conical. Exostome well developed; teeth cross-striolate below, papillose above, slightly dentate above. Endostome well developed, with high basal membrane; segments not or narrow-perforate along midline; cilia 2-3, as long as segments, nodose. Spores 14.0-21.0(-24.5) µm, finely papillose.

• Distribution

  Cratoneuron includes two species, one of which is widely distributed in temperate to arctic areas and also occurs at higher altitudes in tropical S America.