A taxonomic study of Dumortiera® 
ALEXANDER W. EVANS 
The genus Dumortiera was proposed in 1824 by Nees von 
Esenbeck for the reception of Marchantia hirsuta Sw. This 
species, which dates from 1788, was based on specimens from the 
mountains of Jamaica. Subsequent writers have assigned to it, 
however, a wide geographical distribution, its reputed range in- 
cluding most of the moist tropical and subtropical regions of the 
earth with extensions into certain temperate regions. According 
to the records the other species which have been referred to the 
genus are more restricted in their range, some of them having 
been reported from only one or two localities. These additions 
are not numerous, as the following complete list of species, arranged 
chronologically, will show :— 
DUMORTIERA HIRSUTA (Sw.) Nees, 1824 (Marchantia hirsuta pe —" 
D. Spatuyst (Lindenb.) Nees, 1838 (M. Spathysii Lindenb., 
D. IRRIGUA es “os Nees, 1838 (M. irrigua Wils., 1833, eReat irrigua 
Tayl., 183 
D. NEPALENSIS Soret a Nees, 1838 (H. nepalensis Tayl., 1836); 
D. TRICHOCEPHALA (Hook.) Nees, 1838 (Marchantia ee iy Hook., 1837); 
D. DILATATA (Tayl.) Nees, 1847 (Hygropyla dilatata Tayl., 1844); 
ASKEPOS BREVIPES Griff., ap 
DUMORTIERA DENUDATA Mitt, 1861; 
D. VELUTINA Schiffn., 1898; ‘ 
D. catcrcoLta Campbell, 1918. 
From this list three species may be at once excluded; they do 
not belong to Dumortiera and have already been transferred to 
their proper positions by writers. The species in question are: 
D. Spathysii, which is now regarded as a synonym of Clevea 
Rousseliana (Mont.) Leitg.; D. dilatata, a synonym of Monoclea 
Forsteri Hook.;t and D. denudata, the type species of the genus 
* Contribution from the Osborn Botanical Laboratory. 
+ Leitgeb (7, p. 312) was the first to recognize that H. dilatata was a Monoclea 
and not a Dumortiera. He called it M. dilatata, supposing that it was distinct from 

Lindb., rather than from the true M. Forsteri. The type specimen of H. dilatata in 
« Herbarium shows conclusively that the species is a synonym of M. 
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