The oldest example of paired guard cells and the oldest occurrence of paracytic stomata

The oldest stomata (paracytic) with paired guard cells

Banks H. P. (xxxx)

Harlan P. BANKS,

Division of Biological Sciences, Cornell University, Ithaca, New York, U.S.A. 14853

The Palaeobotanist –


Stomata of the lycopod Drepanophycus spinaeformis were collected by Lang
(1932) in Early Devonian strata of Siegenian age (390-374 million years ago).

They are reinterpreted on the basis of a study of stomata from younger (Emsian,
Givetian, Frasnian) collections. These plants are shown to have a paracytic
stomatal apparatus. Lang therefore found the oldest example of paired guard
cells and the oldest occurrence of paracytic stomata among vascular plants.

Stomata in Selaginella

Morphological and phylogenetic evidence that the novel leaf structures of multivein Selaginella schaffneri are derived traits

Liu J.-W., Huang C.-L., Valdespino I. A., Ho J.-F., Lee T.-Y., Chesson P., Sheue C.-R. (2021)

Jian-Wei Liu a; Chun-Lin Huang b, Iván A. Valdespino c, Jia-Fang Ho ab, Tzu-Yun Lee a, Peter Chesson ad, Chiou-Rong Sheue ad,

a Department of Life Sciences & Research Center for Global Change Biology, National Chung Hsing University, 145 Xingda Rd., South Dist., Taichung City 402202, Taiwan

b Laboratory of Molecular Phylogenetics, Department of Biology, National Museum of Natural Science, No.1, Guancian Rd., North Dist., Taichung City 404605, Taiwan

c Departamento de Botánica, Facultad de Ciencias Naturales, Exactas y Tecnología, Universidad de Panamá; Sistema Nacional de Investigación (SNI), SENACYT, Panama, Panama

d Department of Ecology and Evolutionary Biology, University of Arizona, 1041 E. Lowell St., Tucson, AZ 85721, USA


DOI: 10.1016/j.flora.2021.151976


• The structure of multivein Selaginella schaffneri supports the microphyll concept.

• Leaf veins originate from a vein node derived from a single strand with no leaf gap.

• The microphylls have bundle sheath cells and multiple stomatal types.

S. schaffneri is the earliest diverging lineage within subgenus Stachygynandrum.

Homoplasy with angiosperms in complex derived drought resistance traits.



Microphylls, simple leaves with a single vein and no leaf gap, are the typical lycophyte leaves. However, Selaginella schaffneri has complex veins. Structural features and phylogeny associated with this unusual venation have remained unknown. We studied the leaf, venation, spore structures, and phylogeny of S. schaffneri, with S. erythropus as a typical Selaginella for comparison.

Leaf veins of both S. schaffneri and S. erythropus originate from a single vascular strand in the stem and have no leaf gaps. In S. schaffneri, this single vascular strand prominently enlarges as a hub-like vein node at the leaf base and then divides multiply in the leaf blade.

Unusual structures, more commonly found in angiosperms, are revealed, including vessels, bundle sheath cells, three stomatal types, and differentiated mesophyll tissue. Other unusual structures include transparent zones on the leaf margin and a complex open hexagonal three-dimensional structure on the megaspore walls. Fifty one concatenated protein-coding genes from plastomes were used to construct the phylogeny of S. schaffneri within Selaginellaceae, which shows that S. schaffneri, together with the sanguinolenta group, is the earliest-diverging lineage of subgenus Stachygynandrum. The unusual structures of S. schaffneri are consistent with drought resistance. However, these structures are not known in more basal members of Selaginella and appear to be derived in S. schaffneri. The leaf veins of S. schaffneri, originating from the branching of a single vein, imply a variation on a microphyll. Despite the general simplicity of structure in Selaginella, S. schaffneri shows unusual structural homoplasy with angiosperms in these traits.

Stomata in Lycopodiaceae and Selaginellaceae

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Stomatal Function

by Zeiger E., Farquhar G. D., Cowan I. R. (1987)

Eduardo Zeiger, G.D. Farquhar, I. R. Cowan,


in Stanford University Press –

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Stomata in Selaginella ciliaris



A New Taxonomic Circumscription and Record of Selaginella ciliaris (Selaginellaceae) from Terrai Regions of Uttar Pradesh

by Johari D., Singh A. P. (2016)

Pteridology Laboratory, CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, U.P. 226 001, India

Deepali Johari,

Ajit Pratap Singh,


in National Academy Science Letters 40(1) – DOI: 10.1007/s40009-016-0518-1 –

Selaginella ciliaris (Retz.) Spring, a lycophyte have been encountered from Dudhwa National Park and Katarniaghat Wildlife Sanctuary, which is a new record from terrai regions of Uttar Pradesh.
Presence of stomata on lateral and median leaves provides an additional taxonomic circumscription to the species. Taxonomic account, line-drawing illustrations, photographs, vegetative and reproductive attributes including microsporophyll, megasporophyll and distribution pattern across the region have been provided with an emphasis on stomata of marginal and mid-vein region of leaves.



Stomata in Selaginella (Lycopsida)



Novelties in Selaginella (Selaginellaceae – Lycopodiophyta), with emphasis on Brazilian species

by Valdespino I. (xxxx)

Iván Valdespino,


in PhytoKeys 57: 93-133 –


In this paper, I describe five new species of Selaginella from Brazil (S. nanuzaeS. neospringianaS. pellucidopunctataS. stomatoloma, and S. trygonoides), compare them to morphologically similar species, and provide a preliminary conservation status assessment for each. The new species are illustrated with scanning electron photomicrographs of stem sections, leaves, and spores, when available. Also discussed in this paper are ten species, mainly from Brazil and with new distribution records, and the forthcoming resurrection of three species also occurring in Brazil. Three further non-native and presumed naturalized species are recognized in Brazil, and publication of one additional taxon is planned. Eighty-six Selaginella species are now known from Brazil and, of these, 80 are native (including 26 / 32.5%, endemic), and six are introduced. Brazil and Mexico have the second highest number of native Selaginella species in the Neotropics after Venezuela, which is estimated to have about 100. Of the newly documented species, S.cabrerensis is now known to occur in French Guiana, Brazil, and Bolivia, in addition to Colombia, and S. arroyoana and S. chiquitana are synonymized under it. Likewise, S. potaroensis is also recorded from Costa Rica and Brazil, and S. seemannii from Panama and Brazil. Finally, leaf marginal stomata are reported on the newly described species and their functionality is discussed under S. stomatoloma.

Selaginella stomatoloma Valdespino. A Section of upper surface of stem B Upper surface of median leaf C Close-up of base and proximal portion of median leaf, upper surface; note marginal (a) and submarginal stomata (b) D Close-up of proximal portion and apex of median leaf, upper surface; note marginal (a) and submarginal (b) stomata E Section of lower surface of stem F Lower surface of lateral leaf; note marginal stomata (a) G Close-up of base and proximal portion of lateral leaf, lower surface; note marginal (a) and submarginal (b) stomata H Upper surface of lateral leaf. A–H taken from the holotype, Almeida et al. 2518 (PMA).

upper surfaces comprising quadrangular to rounded, sinuate-walled, glabrous cells, with stomata submarginal, particularly on distal ½ and throughout margins, lower surfaces comprising elongate, sinuate-walled, glabrous cells, with stomata in 3–5 rows along midribs and throughout acroscopic halves of the laminae.



En este artículo describo cinco nuevas especies de Selaginella de Brasil (S. nanuzaeS.neospringianaS. pellucidopunctataS. stomatoloma y S. trygonoides), las cuales comparo con especies morfológicamente similares y estimo, preliminarmente, su estado de conservación. Las nuevas especies las ilustro con fotomicrografías al microscopio electrónico de barrido de secciones de los tallos, hojas y esporas (cuando están disponibles). Diez especies adicionales son discutidas en este artículo con nuevos registros, mayormente para Brasil, y la resurrección de otras tres también presentes en este país es anunciada. Tres especies introducidas y presuntamente naturalizadas adicionales son documentadas en Brasil, mientras que se anuncia la publicación próximamente de una especie nueva que también ocurre en este país. Por lo tanto, la ocurrencia de 86 especies de Selaginella en Brasil es conocida ahora, de las cuales 80 son nativas (26 de ellas o el 32.5% son endémicas) y seis son introducidas. Brasil y México tienen el segundo mayor número de especies nativas de Selaginella en el Neotrópico, después de Venezuela que se estima que posee unas 100. De las especies documentadas por primera vez, S.cabrerensis se reconoce que está distribuida en Guayana Francesa, Brasil y Bolivia, además de Colombia, y se consideran formalmente como sinónimo de ésta a S. arroyoana y a S. chiquitana. Adicionalmente, S. potaroensis es documentada en Costa Rica y Brasil, al igual que lo es S.seemannii en Panamá y Brasil. Finalmente, la presencia de estomas en los márgenes de las hojas se reporta en las cinco nuevas especies descritas y su funcionalidad se discute bajo S.stomatoloma.

The marginal stomata in Selaginella appear to be non-functional

Selaginella rivalis. A. Axillary leaves; B. leaf border showing marginal stomata; C. laminal stomata of Selaginella rivalis: note that the subsidiary cells of the stomata are indistinguishable from laminal cells.


The Non-Functional Stomata on the Leaf Margin of Selaginella

by Yi Y., Tan B. C. (xxxx)

Yi Youguang and Benito C. Tan

Department of Biological Sciences, National University of Singapore, Singapore 119267


in Philippine Journal of Science 142: 245-248, Special Issue ISSN 0031 – 7683 –

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Apical leaf cells of lateral leaf and lateral outline of Selaginella roxburghii. Black dot indicates a leaf bordered stomata structure.



Stomata are structures on the surface of leaves known for their function in gaseous exchange in plants. After examining 26 species of Selaginella collected from Peninsular Malaysia and Singapore, we discover and report the presence of stomatal structures that are located right on the border of adaxial surface of lateral and axillary leaves of four species of Selaginella (S. roxburghii, S. ridleyi, S. rivalis and S. ciliaris).

The marginal stomata appear to be non-functional due to their position on the leaf border which is one to two cells thick.

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Selaginella ciliaris. A. SEM photograph of margin of adaxial surface of lateral leaf of S. ciliaris showing the stomatal opening (750×); B. Line drawing of margin of adaxial surface of lateral leaf of S. ciliaris showing the stomata (400×).

Stomata of Huperzia (Lycopodiaceae) under Different Light Treatments

Photo credit : Google

Huperzia serrata (Lycopodiaceae)


Morphology of Huperzia serrata and Its Stomata Characteristics under Different Light Treatments

by Li Y.-Y., Tang Y.-J., Li J., Zhou Y., Huang H.-Y. (2009)

LI You-You; TANG Yuan-Jiang; LI Jing; ZHOU Yi; HUANG Heng-Yu*
(1.Key Laboratory of Plant Resources Conservation and Utilization(Jishou University),College of Hunan Province,Jishou416000) (2.South China Botanical Garden,The Chinese Academy of Sciences,Guangzhou510650)


in Bulletin of Botanical Research (BBR) 29(4): 411-416 – –


The morphological characteristics of Huperzia serrata (Thunb.) Trev. were described, and a few different characteristics were found. In addition, the relationship between the stomata characteristics and the illumination intensity was analyzed.

The results showed the length, width and area of single stomata, the stomata density and the total stomata area increased when the illumination intensity kept rising within a certain limit.

However, all of these stomata parameters decreased when the illumination intensity surpassed a certain value except the stomata density and the stomata index. The stomata of small sizes and high densities were the characteristics fitted for the arid conditions, indicting that this plant was ecological adaptive, but when it was under cultivation high illumination intensity should be avoided.



Stomata in Japanese Selaginellaceae


Systematic importance of the epidermal elements in the leaves of the Japanese Selaginellaceae

by Satake Y. (1934)


in Bot. Mag. Tokyo 48: 259-278 – –

Twenty four species of the Japanese Selaginellae are examined for the purpose of discussing the systematic importance of the epidermal elements of leaves.

Stomatal control and gene signalling networks in bryophytes and lycophytes


Early evolutionary acquisition of stomatal control and development gene signalling networks.

by Chater C., Gray J. E., Beerling D. J. (2013)

Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.

in Current Opinion in Plant Biology 16 : 638 – 646  – doi: 10.1016/j.pbi.2013.06.013. –


Fossil stomata of early vascular land plants date back over 418 million years and exhibit properties suggesting that they were operational, including differentially thickened guard cells and sub-stomatal chambers.

Molecular studies on basal land plant groups (bryophytes and lycophytes) provide insight into the core genes involved in sensing and translating changes in the drought hormone abscisic acid (ABA), light and concentration of CO2 into changes in stomatal aperture.

These studies indicate that early land plants probably possessed the genetic tool kits for stomata to actively respond to environmental/endogenous cues. With these ancestral molecular genetic tool kits in place, stomatal regulation of plant carbon and water relations may have became progressively more effective as hydraulic systems evolved in seed plant lineages.

Gene expression and cross-species gene complementation studies suggest that the pathway regulating stomatal fate may also have been conserved across land plant evolution.

This emerging area offers a fascinating glimpse into the potential genetic tool kits used by the earliest vascular land plants to build and operate the stomata preserved in the fossil record.