SYNOPSIS OP OEDERS AND GENERA. 55 



Oedee XXI. ZYGODOJSTTHI. 



Sporangium striated ; peristome 0, single or double ; veil cu- 

 cullate, smooth. 



Genus 69. Zygodon. — Sporangium apophysate; veil small, 

 oblique; peristome 0, single, or double. 



Oedee XXII. OBTROTRIOREL 



Sporangium mostly striated ; veil mitriform, plicate, mostly 

 pilose; peristome variable. 



Genus 70. Orthotrichum. — Sporangium striate; veil with 

 a few keel-like folds ; leaves not curled when dry. 



Genus 71. Ulota. — Sporangium striate; veil with many 

 folds ; leaves curled when dry. 



Oedee XXIII. PTYGEOMITBIEL 



Sporangium without a tapering apophysis; veil smooth, 

 furrowed, subulate ; leafrcells punctiform, even. 



Genus 72. Ptychomilrium. — Sporangium slightly tapering 

 below ; veil deeply furrowed, laciniate ; peristome of sixteen 

 deeply-divided teeth. 



Genus 73. Glyphomitrium. — Sporangium roundish ; veil 

 large, ventricose, plicate, laciniate ; peristome of sixteen teeth, 

 disposed in pairs. 



Oedee XXIV. GBIMMIEI. 



Sporangium equal ; veil mitriform ; leaves mostly with an 

 excurrent nerve ; upper leaf-cells punctiform. 



Genus 74. Racomitrium. — Veil multifid below, subulate 

 and papillose above ; ring large ; peristome of sixteen bi-trifid 

 teeth, sometimes divided »to the base; lower leaf-cells narrow. 



Genus 75. Grimmia. — Veil mitriform or cucullate; peri- 



