74 LESKEACEAE 



2 — Plants bluish or glaucous green (scarcely so in T. hirtella); leaf 



papillae very large, often lobed or branched; paraphyllia lacking. . 3 

 Not bluish or glaucous green; papillae smaller, or rarely lacking; 



paraphyllia present except in Anomodon and part of Leskea 4 



3 — Costa short or double Myurella 



Costa single, usually reaching the middle of the leaf Thelia 



4 — Costa double or short or almost lacking. (See also Leskea denticn- 



lata) Pterigynandrum 



Costa single, strong 5 



5 — 9 buds and sporophytes borne on secondary stems; paraphyllia 



lacking Anomodon 



9 buds and sporophytes borne on primary stems; paraphyllia present 

 in part of the species Lindbergia and Leskea 



THUIDIUM B. & S. (Plate VIII.) 



The Thuidia are widely distributed and have been noted by 

 every lover of out-of-door life because of their delicate and 

 beautiful fern-like form. The branches are given off very 

 regularly like the pinnae of a fern, and the branches themselves 

 often give off branchlets as regularly as the pinna of a fern is 

 divided into pinnules. 



The steins bear paraphyllia of various sizes and shapes, but 

 all are more or less linear or filamentose, often divided and 

 branched, but not leaf-like. There is often considerable dif- 

 ference between the stem and branch leaves in shape and size. 

 The ovate-triangular stem leaves are usually papillose on both 

 surfaces, unicostate, the costa passing the middle. The median 

 leaf cells vary from roundish quadrate-hexagonal to rhombic- 

 oblong; in two species linear-rhomboidal. The capsules, on 

 smooth pedicels, are annulate, more or less curved. The oper- 

 cula vary from conic to rostrate; the peristomes are well de- 

 veloped; the endostomial band }/% the length of the teeth, with 

 segments and cilia. 



Key 

 I — Apical cells of branch leaves crowned with 2-4 papillae; median cells 



quadrate-hexagonal to oblong-rhomboidal 2 



Apical cells of branch leaves with a single terminal papilla; median 



cells as in 2. Paraphyllia numerous, branched 7 



Apical cells of branch leaves not papillose; median leaf cells linear- 

 rhomboidal. Paraphyllia long-linear or filamentose paludosum 



2 — Paraphyllia few, small, linear-oblong, 2-6 cells long; branch leaves 



subcrispate-incurved when dry 3 



Paraphyllia numerous, more or less branched 4 



