1962] 



LEAF'S HEP ATI CAE OF LATIN AMERICA — PART 1 



79 



16. Isotachis spegazziniana Massalongo, Nuovo Gior. Bot. Ital. 17: 220. pi, 

 16, f. x. 1885. 



Plants of small to medium size, dark brown, ascending to erect, in tufts ; 

 stems 4-6 em long, with leaves to 1.5 mm wide, occasionally branched; stems in 

 transverse section 12-15 cells in diameter, the cells of the cortical band in one 

 or two rows, smaller, with thicker walls than those of the medulla. Rhizoids 

 not seen. Leaves spreading, subimbricate, orbicular, often cucullate, notched 

 for one-sixth of their length or less, the sinus small. V-shaped ; cells of the medi- 

 an portion averaging 36 X 17 /*, the walls thickened, the intermediate thicken- 

 ings and trigones conspicuous, the cuticle smooth. Underleaves scarcely distin- 

 guishable from the leaves. Female inflorescence terminal on the stem, the bracts 

 and bracteoles similar to the leaves and underleaves, larger, the bracts of the in- 

 nermost scries undivided. Perigynium 4-5 mm long, arcuate, the mouth short- 

 ciliate, hyaline, the wall four to six layers of cells thick below, the outermost 

 layer often hyaline, the inner wall with occasional papillae. Sporophyte (very 

 young) enclosed in a shoot-ealyptra with scattered unfertilized archegonia on 

 the surface, the foot enclosed in a thin covering, the capsule long-cylindric. 

 Male inflorescence not seen. Fig. 16, a-j. 



Habitat: In water and on soil in wet areas. 



PATAGONIA— TIERRA DEL FUEGO: Desolation I., Puerto Angosta, Dusen 138, 

 184, 388, 587 (G) ; Rio Azopardo, Duscn 97 (G) ; Basket I., Desolation Bay, Spegazsini 195 

 (type VER). 



The following taxa now in the genus Isotachis have not been included in 

 the present study, either because the types were not available or because the 

 material was not conclusive. All need further study. 



Isotachis allionii Stephani, Ecuador. 

 Isotachis boliviensis Gottsche ms. 



Isotachis dctitata Stephani ms., Icones Hep. Isotachis No. 52. Patagonia. 



Isotachis fucgiensis Stephani, Patagonia. 



Isotachid g^-a\nditexta Stephani, Patagonia. 



Isotachis hians Stephani, Bolivia. 



Isotachia homophylla (Nees) Stephani, Brazil. 



Isotachis mascida Gottsche, Colombia. 



Isotachis quadriloba Stephani, Patagonia. 



Isotachis stubelii Stephani ms., Icones Hep., Isotachis No. 29, Colombia. 

 Isotachis valida Stephani, Patagonia. 

 Isotachis vexans Stephani, Venezuela. 



There have been a number of additional subspecific taxa described by vari- 

 ous authors at various times. 



