LA FARGE, CATHERINE. Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9. - The Circumscription of the Dicranaceae (Bryopsida), with special emphasis on the subfamily Dicranoideae Based on cp DNA: trnL and rps4.
Chloroplast DNA regions (trnL(UAA) - trnF (GAA)) are used to explore the systematic
relationships of families and subfamilies within the Dicranales. Special emphasis is given to
subfamily Dicranoideae of the Dicranaceae, with 17 of the 23 genera represented. 77 taxa are
sequenced for trnL - trnF and 69 for rps4, 1247 characters were aligned in the final matrix,
of which 1000 characters were used for the analyses. The combined data set was analyzed
using maximum parsimony (MP) and maximum likelihood (ML) to examine the generic and familial
relationships within the order. Bootstrap values and decay indices show that our data
support the following relationships within the Dicranales: 1) the Dicranaceae are
polyphyletic, 2) the subfamilies Paraleucobryoideae and Dicranoideae are polyphyletic, 3) the
Rhabdoweisiaceae (cf Vitt 1984) are expanded to include members of the Dicranaceae, 4) the
subfamily Campylopodioideae has a firm sister relationship to the Leucobryaceae, 5) the
Dicranelloideae are excluded from the Dicranaceae sensu stricto, 6) the Dicnemonaceae form a
monophyletic clade, including Mesotus (subfamily Mesotoideae, cf Allen 1987) that are nested
within the Dicranaceae, and 7) the Ditrichaceae are polyphyletic. The cpDNA data strongly
suggest the need for a reevaluation and circumscription of the Dicranaceae. Within the
Dicranaceae sensu stricto there are 4 major clades: 1) Leucoloma - Sclerodontium as the basal
clade, 2) Dicranoloma - Braunfelsia - Cryptodicranum - Holodontium, 3) Chorisodontium -
Orthodicranum - Paraleucobryum - Dicranum - Eucamptodontopsis -Schliephackea - Holomitrium,
and 4) Dicnemon,- Eucamptodon - Mesotus clade. Excluded from the Dicranaceae sensu stricto
are Arctoa, Brothera, Campylopus, Cynodontium, Dicranella, Dicranodontium, Dicranoweisia,
Hydrodicranum, Kiaeria, Kingiobryum, Oncophorus, Oreas, Symblepharis, and Trichodontium.
Key words: cpDNA, Dicranaceae, Dicranoideae, molecular data, phylogenetics