Cheilolejeunea

• Authority

  Gradstein, S. Robbert & Ilkiu-Borges, Anna L. 2009. Guide to the plants of Central French Guiana. Part 4. Liverworts and hornworts. Mem. New York Bot. Gard. 76 (4): i-iv + 1-140.

• Family

  Lejeuneaceae

• Scientific Name

  Cheilolejeunea

• Description

  Description - Plants small to medium-sized, rather dull, pale green to olive-green to brown, creeping to ascending, rarely pendent. Branches Lejeunea- type. Stems usually with enlarged epidermis, cells ± thick-walled; ventral merophyte 2(6) cells wide. Leaf lobes obliquely to widely spreading when dry, apex rounded to acute, plane or recurved, margins entire or sinuate due to mammillose or tuberculate cells. Cells subisodiametrical, plane or mammillose, sometimes with a broad, lenticular papilla, trigones small to large, intermediate thickenings scarce; oil bodies very large, 1-4 per cell, sausage-shaped, coarsely granular; ocelli lacking. Lobules small or large, not reduced, rather strongly inflated with inflexed free margin, constricted at apex, first tooth reduced, second (apical) tooth 1 -celled, short-obtuse or long-sharp, hyaline papilla distal. Underleaves bifid or undivided, margins entire, insertion line shallowly curved to arched. Androecia on short, specialized branches, bracteoles limited to base or present throughout, bracts with hypostatic lobules. Gynoecia on long or short shoots, without or with 1-2 lejeuneoid or pycnolejeuneoid innovations. Perianths with 4-5 smooth keels. Sporophyte lejeuneoid. Vegetative reproduction rare, by caducous leaves. Trachylejeunea (Spruce) Schiffn. as redefined by He and Grolle (2001), including only species of the subgenus Trachylejeunea (Schuster 1980), is very similar to Cheilolejeunea and is treated here as a synonym. The only difference between the two genera is the presence of two well-developed, lobule teeth in Trachylejeunea. In Cheilolejeunea, the first lobule tooth is normally reduced, and only the second is well-developed (hence, the hyaline papilla is distal to the tooth). However, several species of Cheilolejeunea, e.g., the common C. trifaria, may possess a small, first tooth. These species are clearly intermediate between Trachylejeunea and Cheilolejeunea. The lack of morphological difference does not warrant recognition of the two groups at the generic level. Because the two genera were established at the same time, the smaller of the two (Trachylejeunea) is reduced here to synonymy to minimize the number of necessary new combinations.

• Discussion

  The synonymy of Trachylejeunea under Cheilolejeunea requires the following new combinations:

  Cheilolejeunea acanthina (Spruce) Gradstein & Ilkiu-Borges, comb. nov. (Lejeunea acanthina Spruce, Trans. & Proc. Bot. Soc. Edinburgh 15: 182. 1884; Trachylejeunea acanthina (Spruce) Schiffn.)
  Cheilolejeunea asperiflora (Spruce) Gradst. & Ilkiu-Borges, comb. nov. (Lejeunea asperiflora Spruce, Trans. & Proc. Bot. Soc. Edinburgh 15: 183. 1884; Trachylejeunea asperiflora (Spruce) Schiffn.)
  Cheilolejeunea polystachya (Spruce) Gradst. & Ilkiu-Borges, comb. nov. {Lejeunea polystachya Spruce, Trans. & Proc. Bot. Soc. Edinburgh 15: 250. 1884; Trachylejeunea polystachya (Spruce) Steph.)