238 A MANUAL OF MOSSES 



h. Cilia 3, smooth; cells of stem-leaves elongate-hexagonal to al- 

 most linear; stem and branch-leaves similar. 



11. Elodium. 

 h. Cilia 2-4, nodose to appendiculate: cells of stem-leaves rounded- 

 angular to long-hexagonal. i. 

 i. Operculum merely sharply acute: costa of stem-leaves percurrent 

 to excurrent; leaf-margins indistinctly serrate above. 



9. Haplocladiuin. 

 i. Operculum distinctly rostrate: costa incomplete to excurrent; stem- 

 and branch-leaves dissimilar. j. 



j. Margin of stem-leaves entire, base not decurrent; cells uniform, 

 rounded-angular, the median with 2-6 papillae on each side. 



8. Rauia. 

 j. Margin of stem-leaves entire or toothed above, the base some- 

 what decurrent; cells mostly uniform, rounded- to oval- or 

 oblong-hexagonal, the median ranging from dorsally unipapil- 

 lose to both sides pluri-papillose. 10. Thuidium. 



1. THELIA Sullivant. 



Dioicous : more or less slender, densely cespitose, yellow- 

 ish to blue-green, dull: stem elongate, creeping, more or less 

 brown-radiculose, densely-leaved, thickly pinnately branched; 

 branches short, julaceous, obtuse, erect to ascending; para- 

 phyllia various ; leaves densely imbricate, either dry or moist, 

 more or less decurrent, spoon-like, broadly ovate, abruptly 

 subulate-acuminate, the margins plane, mostly ciliate-serrate 

 to laciniate; costa short, simple or forked; cells rhombic, each 

 dorsally with a high and one- to several-pointed papilla; 

 median basal leaf-cells elongate, the alar in several series al- 

 most quadrate ; inner perichsetial leaves larger, delicate, erect, 

 oblong and subulate-acuminate, with long marginal cilia, costa 

 ending in mid-leaf, areolation elongate, the upper cells uni- 

 papillose above: seta 5-15 mm. long, thin, drying twisted, 

 smooth and red ; capsule symmetric, erect, oblong to cylindric, 

 golden-brown ; annulus none ; peristome-teeth basally con- 

 fluent, narrowly linear-lanceolate, pale, non-bordered, finely 

 papillose, distantly articulate, non-trabeculate ; inner peris- 

 tome pale, papillose, distantly lamellate, non-trabeculate ; inner 

 peristome pale, papillose ; basal membrane low, segments very 

 short or rudimentary, cilia none; lid conic, short-rostrate; 

 calyptra cucullate, smooth ; spores small. 



A North American genus of but five species ; three species 

 in our region. 



Key to the Species. 



a. Papillae on dorsal surface of leaf long, curved, with one point. 



1. T. hirtelh. 



a. Papillae on dorsal leaf-surface lower, each with two or more points. 



b. 

 b. Papillae usually two-pointed; leaves ciliate. 



2. T. asprella. 

 b. Papillae usually 3 or 4 pointed; leaves non-ciliate. 



3. T. lescurii. 



