Belongs within: Jungermanniales.
The Geocalycaceae are a cosmopolitan family of leafy liverworts. It has been divided by some authors into separate families Geocalycaceae and Lophocoleaceae, based (among other features) on the presence (Lophocoleaceae) or absence (Geocalycaceae) of a perianth.
Some like it cold
Published 24 August 2010
I’m not providing you with an image of the species that was the intended subject of this section, because I haven’t been able to find one. The figures below from Gao et al. (2001) show other species in the same genus from China:
Leafy liverworts are small plants that are superficially similar in appearance to mosses. Like mosses, they grow in moist localities and lack well-developed supporting vascular tissue. Leafy liverworts can often be distinguished from mosses by having a different arrangement of leaves (liverwort leaves often grow in lateral rows, moss leaves in spirals), lacking a median vein in the leaf and potentially having teeth or lobes on the edge of the leaf. Liverworts also have different reproductive structures from mosses; instead of opening with a cap, liverwort spore capsules usually split down the sides.
Saccogynidium vasculosum is a species of liverwort restricted to the Falkland Islands and the very southernmost part of South America (Engel 1990; Frey & Schaumann 2002). Earlier authors referred to it as Lophocolea vasculosa but this was due to confusion with a different species, L. elata, from which it can be distinguished by the presence of small papillae (bumps) covering the leaves, a feature of the genus Saccogynidium (Engel 1978). Saccogynidium is also distinguished from related genera by producing the female reproductive organs inside a fleshy protective covering called a marsupium (one is shown in the lower part of the figure above). Saccogynidium vasculosum is distinguished from other species in the genus by having finer papillae on the leaves, and having the tips of the leaves narrowly rounded rather than two-pointed.
Whar’s really notable about Saccogynidium is its distribution (Schuster 1972). As well as S. vasculosum, the Falkland Islands are home to S. australe, a species also found in New Zealand. Other species are found in Tasmania and south-east Asia. Interesting questions could be asked whether the current distribution of Saccogynidium is due to Gondwanan ancestry (in which case the disjoint distribution of S. australe might argue for incredibly slow rates of evolution) or to more recent dispersal, something some authors seem to have dismissed out of hand.
Systematics of Geocalycaceae
Characters (from Hong 1993): Dioicous, autoicous, or paroicous gametangia; lateral and ventral intercalary or terminal branching; succubous or obliquely inserted leaves; bilobed underleaves; rhizoids restricted to base of underleaves or scattered over ventral surface of stem; lateral or ventral fertile branches; slenderly spicate androecia; large, reduced, or vestigial female bracts; perianth reduced or absent, or with a rhizoidal perigynium, or wide mouthed; ovoid to cylindric capsule with 2-5 layered walls.
<==Geocalycaceae [Geocalycineae, Lophocoleaceae] |--HeteroscyphusG06 | |--H. argutusG06 | |--H. bescherelleiG06 | |--H. combinatusJ87 | |--H. flaccidusG06 | |--H. inflatusG06 | |--H. pandeiG06 | `--H. tenerG06 |--LeptoscyphusFHH01 | |--L. amphiboliusJ87 | `--L. horizontalisFHH01 |--ChiloscyphusFHH01 | |--C. beckettianusM49 | |--C. bidentatusM49 | |--C. billardieriM49 | |--C. coalitusE03 | |--C. cuneistipulusM49 | |--C. cymbaliferusM49 | |--C. decipiensM49 | |--C. echinellusM49 | |--C. fissistipusM49 | |--C. grandiflorusE03 | |--C. integrifoliusE03 | |--C. laxusM49 | |--C. lyalliiM49 | |--C. massalongoanus Steph. 1893 [incl. C. fissistipus var. magellanicus Schiffn. & Gottsche 1890]E03 | |--C. menziesiiM49 | |--C. normalisM49 | |--C. oblongifoliusM49 | |--C. pallescensSF01 | |--C. paraphyllinusD03 | |--C. polyanthusG06 | |--C. striatellusD03 | `--C. valdiviensisE03 `--LophocoleaFHH01 |--L. anomadaD03 |--L. attenuataD03 |--L. australisM49 |--L. austrigenaE03 |--L. bidentata (Linnaeus) Dumort. 1835 [=Jungermannia bidentata Linnaeus 1753]SS07 |--L. boveanaE03 |--L. campanulataD03 |--L. coadunataJ87 |--L. concavaE03 |--L. conifoliaD03 |--L. cookianaE03 |--L. cucullistipulaD03 |--L. cuspidataG06 |--L. divergenticiliataE03 |--L. fulvellaE03 |--L. fuscovirensE03 |--L. gayanaE03 |--L. gottscheaeoidesE03 |--L. heterophyllaFHH01 |--L. heterophylloidesM49 |--L. homomallaD03 |--L. horizontalis (Hooker) Evans 1903 (see below for synonymy)E03 |--L. humifusaE03 |--L. humilis [=Jungermannia humilis]E03 |--L. irregularisE03 |--L. lacerataE03 |--L. lenta (Hooker & Taylor) Taylor 1845 (see below for synonymy)E03 |--L. leptanthaD03 |--L. leucophyllaM49 |--L. microstipulaD03 |--L. minorM08 |--L. muricataE03 |--L. navicularisD03 |--L. novae-zelandiaeE03 |--L. obvoluta (Hooker & Taylor) Evans 1903 [=Jungermannia obvoluta Hooker & Taylor 1845]E03 |--L. obvolutaeformisE03 |--L. otiphyllaE03 |--L. pallide-virens (Hooker & Taylor) Mitt. 1877 (see below for synonymy)E03 |--L. palustrisE03 |--L. planiusculaM49 |--L. puccioanaE03 | |--L. p. var. puccioanaE03 | `--L. p. var. suspecta Massal. 1885E03 |--L. purpucillaE03 |--L. rigens (Hooker & Taylor) Evans 1903 [=Jungermannia rigens Hooker & Taylor 1844]E03 |--L. sikkimensisG06 |--L. spegazzinianaE03 |--L. stenophylla Schiffn. & Gottsche 1890E03 |--L. subporosaM49 |--L. textilisD03 |--L. trachyopaD03 |--L. trapezoideaJ87 |--L. trialataM49 |--L. triseriataD03 |--L. vasculosa (Hooker & Taylor) Nees 1847 (see below for synonymy)E03 `--L. virensE03
Lophocolea horizontalis (Hooker) Evans 1903 [=Jungermannia horizontalis Hooker 1818, Chiloscyphus horizontalis Nees 1845; incl. J. grandifolia Hooker & Taylor 1844, C. grandifolius Taylor 1845]E03
Lophocolea lenta (Hooker & Taylor) Taylor 1845 [=Jungermannia lenta Hooker & Taylor 1844; incl. J. diademata Hooker & Taylor 1844, J. secundifolia Hooker & Taylor 1844]E03
Lophocolea pallide-virens (Hooker & Taylor) Mitt. 1877 [=Jungermannia pallide-virens Hooker & Taylor 1844, Chiloscyphus pallide-virens Taylor 1845]E03
Lophocolea vasculosa (Hooker & Taylor) Nees 1847 [=Jungermannia vasculosa Hooker & Taylor 1844; incl. J. elata Gottsche 1890]E03
*Type species of generic name indicated
References
[D03] Dusén, P. 1903. The vegetation of western Patagonia. In: Scott, W. B. (ed.) Reports of the Princeton University Expeditions to Patagonia, 1896–1899 vol. 8 Botany pp. 1–34. The University: Princeton (New Jersey).
Engel, J. J. 1978. A taxonomic and phytogeographic study of Brunswick Peninsula (Strait of Magellan) Hepaticae and Anthocerotae. Fieldiana: Botany 41.
Engel, J. J. 1990. Falkland Islands (Islas Malvinas) Hepaticae and Anthocerotophyta: a taxonomic and phytogeographic study. Fieldiana: Botany, new series 25.
[E03] Evans, A. W. 1903. Hepaticae collected in southern Patagonia. In: Scott, W. B. (ed.) Reports of the Princeton University Expeditions to Patagonia, 1896–1899 vol. 8. Botany 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.
Frey, W., & F. Schaumann. 2002. Records of rare southern South American bryophytes. Studies in austral temperate rain forest bryophytes 18. Nova Hedwigia 74 (3–4): 533–543.
Gao, C., T. Cao & M.-J. Lai. 2001. The genus Saccogynidium (Geocalycaceae, Hepaticae) in China. Bryologist 104 (1): 126–129.
[G06] Ghosh, J. P. 2006. A preliminary check-list of hepatics of West Bengal. Bulletin of the Botanical Survey of India 48: 73–102.
Hong, W. S. 1993. The family Geocalycaceae (Hepaticae) in North America, west of the Hundredth Meridian. Bryologist 96 (4): 592–597.
[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.
[M08] Marstaller, R. 2008. Moosgesellschaften am Südrand des Kyffhäusergebirges bei Bad Frankenhausen (Kyffhäuserkreis). 130. Beitrag zur Moosvegetation Thüringens. Mauritiana 20 (2): 289–348.
[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.
Schuster, R. M. 1972. Continental movements, “Wallace’s Line” and Indomalayan-Australasian dispersal of land plants: some eclectic concepts. Botanical Review 38 (1): 3–86.
[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: 1–14.
[SF01] Stech, M., & W. Frey. 2001. CpDNA-relationship and classification of the liverworts (Hepaticophytina, Bryophyta). Nova Hedwigia 72 (1–2): 45–58.