Metzgeriales

Symphyogyna hymenophyllum, from Blue Tier.
Belongs within: Marchantiophyta.
Contains: Metzgeriineae.

The Metzgeriales is a clade of mostly simple thalloid liverworts, though some display varying degrees of 'leafiness'. They are characterised by the production of archegonia behind the growing point (Smith 1991). Members of the Metzgeriales are found in damp habitats.

Characters (from Smith 1991): Plants dorsiventral, thalloid, with or without well-developed midrib, wings of thallus entire, scalloped or incised into leaf-like lobes (which do not develop from two meristematic cells). Thallus with apical cell with two (rarely three) cutting faces; air chambers absent; median conducting strand present or not; cells usually more than 35 μm wide, thin-walled, without trigones, oil bodies few and large or numerous and small. Rhizoids continuous along ventral surface of midrib. Underleaves absent. Archegonia produced behind growing point, growth of which is continuous (monopodial or anacrogynous), on dorsal surface or on short lateral or ventral branches. Developing sporophyte protected by flap-like or cylindrical pseudoperianth or by scales (such structures never being leafy in origin) or by a fleshy calyptra. Capsule spherical, wall 2–6-stratose, usually dehiscing by four valves; elaterophore present at base or apex of capsule. Spores usually more than 30 μm diameter.

<==Metzgeriales
    |  i. s.: Calycularia [Allisoniaceae] G06
    |           `--C. crispula G06
    |--Hymenophyton [Hymenophytaceae, Hymenophytineae] SF01
    |    |--H. flabellatum SF01
    |    |--H. leptodon M49
    |    |--H. leptopodum SF01
    |    `--H. phyllanthus M49
    |--Pellia [Pelliaceae, Pelliineae] SF01
    |    |--P. endiviifolia (Dicks.) Dumort. 1835 [=Jungermannia endiviifolia Dicks. 1801] SS07
    |    |--P. epiphylla SF01
    |    `--P. neesiana G06
    `--Pallaviciniineae SF01
         |--Pallaviciniaceae [Dilaenaceae] FHH01
         |    |--Pallavicinia SF01
         |    |    |--P. connivens SF01
         |    |    |--P. himalayensis G06
         |    |    |--P. indica FHH01
         |    |    |--P. innovans FHH01
         |    |    `--P. lyellii FHH01
         |    `--Symphyogyna SF01
         |         |--S. brogniartii J87
         |         |--S. circinata D03
         |         |--S. crassicosta M49
         |         |--S. crassifrons E03
         |         |--S. hochstetteri D03
         |         |--S. hymenophyllum SF01
         |         |--S. podophylla SF01
         |         `--S. subsimplex FHH01
         `--+--Verdoornia succulenta SF01
            `--Metzgeriineae SF01

*Type species of generic name indicated

REFERENCES

[D03] Dusén, P. 1903. The vegetation of western Patagonia. In Reports of the Princeton University Expeditions to Patagonia, 1896-1899, vol. 8 – Botany (W. B. Scott, ed.) pp. 1-34. The University: Princeton (New Jersey).

[E03] Evans, A. W. 1903. Hepaticae collected in southern Patagonia. In Reports of the Princeton University Expeditions to Patagonia, 1896-1899, vol. 8 – Botany (W. B. Scott, ed.) pp. 35-62. The University: Princeton (New Jersey).

[FHH01] Frey, W., M. Hofmann & H. H. Hilger. 2001. The gametophyte-sporophyte junction: Unequivocal hints for two evolutionary lines of archegoniate land plants. Flora 196: 431-445.

[G06] Ghosh, J. P. 2006. A preliminary check-list of hepatics of West Bengal. Bulletin of the Botanical Survey of India 48 (1-4): 73-102.

[J87] Judd, W. S. 1987. Floristic study of Morne La Visite and Pic Macaya National Parks, Haiti. Bulletin of the Florida State Museum – Biological Sciences 32 (1): 1-136.

[M49] Martin, W. 1949. The bryophytes of Stewart Island.—Part I. Transactions and Proceedings of the Royal Society of New Zealand 77 (2): 257-277.

[SS07] Singh, S. K. & D. K. Singh. 2007. A preliminary census of Hepaticae and Anthocerotae of Doon Valley. Bulletin of the Botanical Survey of India 49 (1-4): 1-14.

Smith, A. J. E. 1991. The Liverworts of Britain and Ireland. Cambridge University Press.

[SF01] Stech, M., & W. Frey. 2001. CpDNA-relationship and classification of the liverworts (Hepaticophytina, Bryophyta). Nova Hedwigia 72 (1-2): 45-58.