1966] 



LEAFY HEPATICAE OF LATIN AMERICA — -PART II 



235 



This genus is a remarkable example of a reduction series in the gametophyte, 

 from more or less erect, radially symmetric, primitive types of leafy stem to 

 the more simplified (reduced), mostly prostrate, dorsiventral type. The species 

 T. plumulosa and T. tetradactyla have radial, erect, leafy stems. The leaves 

 and underleaves of the stem have six (rarely five) segments, but on each succes- 

 sive branch there is a loss of one or two segments with a corresponding decrease in 

 the number of cortical rows of cells in the axis. Both species also occur in the New 

 Zealand area. The most reduced or simplified species is T. sejuncta. It is wide- 

 spread throughout tropical and subtropical South America and extends up into 

 tlie Northern Hemisphere as far as New York, Ireland and Germany. In the 

 most simple condition the leaf consists of two segments five or more cells long 

 and no lamina, while the underleaf has two segments only two cells long. The 

 stem then consists of only six rows of large cortical cells surrounding the medulla. 

 So far as is known, this is the only species which many be dioicous or autoicous. 



Key to the Species 



. Stem leaves divided to the base into two. three, or rarely four uniseriate segments, or 

 each segment from a base of two cells, these two, four, six, or eight cells joined for 

 at least half their length to form a lamina one-half to one row of cells high. 

 2. Underleaves conspicuously shorter than the leaves, bifid or rarely trifid. 



3. Stems 2-4 cm or more long, the lower cells of the leaf segment mostly 75-100 n 



or more long, the tip cell shorter. 1. T. sejuncta. 



3. Stems at most 1 cm long, fragile. 

 4. Largest cells of the leaf segment to about 70 n long, the upper cells shorter. 



2. T. pseudozoopsis. 



4. Largest cells of the leaf segment 50 /u long or less. la. T. sejuncta var. breviscta. 

 2. Underleaves as long as the leaves and very similar. 

 3. Leaves about 0.32 mm long, the segments often incurved, the cells averaging 



54 /j. long. 3. T. apiahyua. 



3. Leaves about 0.8 mm long, the segments spreading, bristle-like, the cells 



averaging 90-100 n long. 4. T. blepharostoma. 



. Stem leaves with a lamina one to four rows of cells high and six, eight, ten or twelve 



cells wide; underleaves large, essentially like the leaves. 

 2. Stem leaves and underleaves with a lamina four or three rows of cells high, and 



segments four to six cells long; perianth mouth crenulate. 6. T. plumulosa . 



2. Stem leaves and underleaves with a lamina one to three rows of cells high; mouth 

 of the perianth long ciliate. 

 3. Stem leaves with a lamina two cells high at the margin, three or four cells high 



between, lower cells of the segments about 70 X20-25 n- 5. T. tetradactyla. 



3. Stem leaves with a lamina two or even only one row of cells high. 

 4. Stem leaves and underleaves stiff, erect-spreading, bristle-like, cells of the 



segment 90-100 v long. 4. T. blepharostoma. 



4. Stem leaves and underleaves with the segments often incurved toward the 

 stem, never bristle-like; cells of the segment under 60 fi long. 

 5. Leaf lamina of two distinct rows of cells; cilia of the bracts and perianth 

 mouth with distinct spines and branches (not known from South America). 



7. T. neesii. 



5. Leaf lamina of only one row of cells; the cilia of the perianth without spines 



or branches. 3. T. apiahyna. 



1. Telaranea sejuncta (Angstrom) S. Arnell, Bot. Not. 110: 17. /. 132-147. 



1957. 



Blepharostoma sejuncta Angstrom, Ofvers. Vet.-akad. Forhandl. 33 (7): 78. 1876. 

 Jungermannia nematodes Gottsche, Hep. Cub. Wright. Nomen nudum. 

 Cephalozia nematodes Austin, Bull. Torrey Club 6: 302. 1879. 

 Lepidozia bicruris Stephani, Hedwigia 24: 166. t. 3. 1885. 



Lepidozia chaetophylla Spruce, Trans. Proc. Bot. Soc. Edinb. 15: 362, 365. 1885. 



