54 DICRANACE/E. 



minute, erecto-patent, slightly twisted when dry, lanceolate from 

 a broader base, the upper lanceolate-subulate, margin sinuosely 

 denticulate, more distinctly so at apex ; nerve narrow, vanishing 

 in the apex or percurrent. Areolation smooth, rhomboid or 

 rectangular and parenchymatous, or longer, narrowly hexagonal 

 and prosenchymatous, wider at base. Perichaetial bracts longer, 

 from a broader concave base, denticulate at apex, forming a 

 comal tuft. Capsule terminal, finally lateral by innovation, 

 immersed, pale yellow. Spores very large, obtusely polyhedral. 

 Antheridia among the perichaetial leaves, with few small bracts. 



Hab. Wet fields and bare spaces ; not common. Fr. spring. 



Varying somewhat in size and habit, and in the form and size of the leaf and of 

 the areolation, this curious little moss has a facies of its own which is hardly like that 

 of any other, even in the barren state ; its resemblance is greatest with Pleuridium 

 alternifolium, but the leaves in that, especially the perichaetial leaves, are much longer, 

 with a much broader nerve, and smaller cells. In Pleuridium axillare the cells are 

 larger and the leaves longer. The fruit, moreover, which is quite distinct in form in 

 the two genera, is usually present in Pleuridium. 



This genus is by Schimper and other authors placed in a separate Order, on 

 account of the peculiar structure of the sporogonium. While, however, in this respect 

 it obviously retains the characters of a primitive form, its vegetative characters so 

 closely resemble those of the next genus as to justify their being placed in close 

 proximity, an arrangement which is also of much greater convenience to the student. 



In the shorter, lower leaves and those on the flagelliform branches, the areolation 

 is usually short and parenchymatous, either rectangular or becoming rhomboidal by 

 the obliquity of the end walls ; at other times, and especially in the elongated 

 perichaetial leaves, it becomes much narrower, elongated and sinuose, often distinctly 

 hexagonal-rhomboid and prosenchymatous. 



The present is the only European species, but there are several closely allied 

 species in N. America. 



10. PLEURIDIUM Brid. 



Minute, cleistocarpous mosses. Leaves lanceolate or lanceo- 

 late-subulate, smooth. Capsule erect, on a short pedicel, im- 

 mersed in the perichsetial leaves, ovate-globose with a short point. 

 Calyptra small, cucullate. Spores rather large, granulose. 



j /Perichsetial leaves similar to the rest ; nerve ceasing below apex i. axillare 



\Pericha?tial leaves much longer than the rest ; nerve reaching apex 2 



fPerichaetial leaves gradually subulate-setaceous, enclosing naked antheridia 



2. subulatum 

 Perichaetial leaves suddenly contracted ; male flowers gemmiform, axillary 



3. alternifolium 



1. Pleuridium axillare Lindb. {Phascum axillare Dicks.; 

 Pleuridium nitidum Rabenh., Schp. Syn.) (Tab. XII. E.). 



Plants small, loosely clustered, pale green. Stems about 

 |-inch high, simple or slightly branched. Leaves patent, slightly 

 twisted when dry, lanceolate or linear-lanceolate, short at base, 



1 



