Stockmansella

Stockmansella; Temporal range:
	Stockmansella langii
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Subdivision:	†Rhyniophytina
Class:	†Rhyniopsida
Order:	†Rhyniales
Family:	†Rhyniaceae
Genus:	†Stockmansella; Fairon-Dem. (1986)[1]
Type species
	Stockmansella langii; (Stockmans 1939) Fairon-Dem. (1986)
Species
	S. langii (Stockmans (1939)) Fairon-Dem. (1986)[1]; S. remyi Schultka & Hass (1997)[2];

Stockmansella is a genus of extinct plants of the Middle Devonian (Eifelian stage, around 393 to 388 million years ago), fossils of which have been found in north-west Germany. The sporophyte generation consists of prostrate dichotomizing stems (axes) up to 10 cm long and around 3mm wide, which at intervals produce narrower smooth upright stems. These bear sporangia (spore-forming organs) on short lateral branches (sporangiophores). The prostrate stems have bulges from which rhizoids form. Both prostrate and upright stems have a central strand of conducting tissue which contains simple tracheids, so that Stockmansella is a vascular plant.[3]

The genus was created by Fairon-Demaret for fossil forms previously assigned to Taeniocrada but which differ in having single lateral sporangia. (She initially gave the genus the name Stockmansia, but this had already been used for a genus of ferns.) The form genus Sciadophyton is thought to be the gametophyte stage of several early land plants, including Stockmansella, although as these forms have only been found as compressed fossils, their morphology is not entirely clear.[3]

In 2004, Crane et al. published a cladogram for the polysporangiophytes, in which Stockmansella is placed in the Rhyniaceae, sister to all other tracheophytes (vascular plants).[4]

Eutracheophytes

	Lycopodiophytina and stem groups

	Euphyllophytina

Rhyniaceae

Huvenia

	Rhynia

	Stockmansella

References

Fairon-Demaret, M. (1986), "Stockmansella, a new name for Stockmansia", Taxon, 35: 334, doi:10.2307/1221284, JSTOR 1221284, cited in Taylor, Taylor & Krings 2009
Schultka, Stephan & Hass, Hagen (1997), "Stockmansella remyi sp. nov. from the Eifelian: new aspects in the Rhyniaceae (sensu Hass et Remy, 1991)", Review of Palaeobotany and Palynology, 97 (3–4): 381–393, doi:10.1016/S0034-6667(96)00074-7
Taylor, T.N.; Taylor, E.L. & Krings, M. (2009), Paleobotany : The Biology and Evolution of Fossil Plants (2nd ed.), Amsterdam; Boston: Academic Press, ISBN 978-0-12-373972-8, pp. 245–6, 248–9
Crane, P.R.; Herendeen, P. & Friis, E.M. (2004), "Fossils and plant phylogeny", American Journal of Botany, 91 (10): 1683–99, doi:10.3732/ajb.91.10.1683, PMID 21652317

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[FaironDemaret1986-1] Fairon-Demaret, M. (1986), "Stockmansella, a new name for Stockmansia", Taxon, 35: 334, doi:10.2307/1221284, JSTOR 1221284, cited in Taylor, Taylor & Krings 2009

[SchultkaHass1997-2] Schultka, Stephan & Hass, Hagen (1997), "Stockmansella remyi sp. nov. from the Eifelian: new aspects in the Rhyniaceae (sensu Hass et Remy, 1991)", Review of Palaeobotany and Palynology, 97 (3–4): 381–393, doi:10.1016/S0034-6667(96)00074-7

[TaylorTaylorKrings2009pp-3] Taylor, T.N.; Taylor, E.L. & Krings, M. (2009), Paleobotany : The Biology and Evolution of Fossil Plants (2nd ed.), Amsterdam; Boston: Academic Press, ISBN 978-0-12-373972-8, pp. 245–6, 248–9

[CraneHerendeenFriis2004-4] Crane, P.R.; Herendeen, P. & Friis, E.M. (2004), "Fossils and plant phylogeny", American Journal of Botany, 91 (10): 1683–99, doi:10.3732/ajb.91.10.1683, PMID 21652317