The stomata of a hybrid cycad combine distinctly the peculiarity found in the contour of the guard cells in both parents.



A morphological comparison of leaflets of a hybrid cycad and the two parents

by Papadopoulos S. (1928)

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Sophia Papadopoulos,


in Botanical Gazette 85(1): 30–45 –


A morphological study of the leaflets of a hybrid cycad obtained from a cross between Ceratozamia mexicana and a new species, Zamia monticola, shows that some of the structures distinctly resemble either one parent or the other, and that other structures show characteristics of both parents.
The stomata illustrate the latter point clearly, as they combine distinctly the peculiarity found in the contour of the guard cells in both parents.



Stomata in Cycas



Scanning electron microscopy studies of cuticle micromorphology in Cycas L. (Cycadaceae).

by Mickle J. M., Barone Lumaga M. R., Moretti A., De Luca P. (2011)


in Plant Biosystems 145: 191–201 – –


A scanning electron microscopy (SEM) study of Cycas cuticle characteristics was undertaken in order to expand our knowledge of microscopic characters not observable under light microscopy and to clarify unresolved affinitites among some species within the genus.

Whole leaf and isolated cuticle specimens from the middle region of leaflets of greenhouse-grown plants of Cycas revolutaCycas rumphiiCycas circinalisCycas media, and Cycas normanbyana were examined using SEM for interior and exterior features.

Characteristics in common include hypostomy, hair bases on abaxial and adaxial surfaces, adaxial cells randomly arranged, adaxial exterior cuticle smooth, and stomata sunken to various degrees but stomatal pit always formed by two layers of epidermal cells.

Stomatal complex is of the polyperigenous type.

Stomata randomly dispersed and oriented, and except C. revoluta, are not contiguous.

Stomata deeply sunken in C. revoluta, intermediate in C. rumphii and C. normanbyana, and less sunken in C. circinalis and C. media.

Aperture between guard cells extends the entire stomatal length in C. rumphii and C. normanbyana, ∼80% in C. circinalis and C. media, and ∼50% in C. revoluta.

Cuticular features of C. revoluta show the greatest difference from the other species in complex relief of exterior cuticle and interior cuticular structure of subsidiary cells; C. media and C. circinalis show close similarity to each other and their stomatal complex dimensions fall within the same unique cluster using principal component analysis under normalized variables.

C. normanbyana and C. rumphii show the most similarity to each other in cuticular micromorphology. Stomatal complex dimensions of these two species fall into a second cluster that also includes C. revoluta. These data contrast with current taxonomy placing C. normanbyanasynonymous to C. media.

Stomata in Cycadaceae

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Cycas (Plat e I. Figs., 1, la , 2, 2a) – Microcycas (Plat e I. Figs. 3, 3a) – Stangeria (Figs, 4, 4a) – Bowetiia (Figs. 5, 5a) – Dioon (Figs. 6, 6a)


Determination of Cycas genera as suggested by leaf epidermis structure

by Greguss P. (n.d.)

Director of Institute for Botany of the University, Szeged, Hungary

* Detail of the author’s work : Xylotomy and leaf epidermis of recent Cycadaceae, in preparation now  –

We hope to offer some help to botanists dealing with recent Cycadaceae but also to paleontologists, when attempting to determine the individual genera by the structure of leaf epidermis on the basis of the following key of determination and two photo-plates. The magnification of the leaves of characteristic representatives of the individual genera (both from surface an d backside) is uniformly 300X .

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Encephalartos (Plate II., Figs. 7, 7a) – Macrozamia, (Lepidozamia) (Figs. 8, 8a, 10, 10a, 11, 11a) – Ceratozamia (Plat e II., Figs. 9, 9a ) – Zamia (Plat e II. Figs. 12, 12a)

Stomata in Zamia (Zamiaceae – Cycadales)

Photo credit: Google

Zamia acuminata

Comparative anatomy of leaflets of Zamia acuminata and Z. pseudomonticola (Zamiaceae) in Costa Rica.

by Acuña-Castillo R. H., Marín-Méndez W. (2013)


in Revista de biologia tropical 61(2):539-46 · June 2013 – DOI: 10.15517/rbt.v61i2.11146 ·

PubMed –

Zamia pseudomonticola –


The genus Zamia is morphologically and ecologically the most diverse of the order Cycadales. Throughout its history this genus has been restricted to the New World and is presently almost entirely restricted to the Neotropics. Unusual anatomical traits of the leaflets, such as the sunken stomata and thick cuticle, are common in this and related genera.

The objective of this research was to study and compare the leaflet anatomy of Zamia acuminata and Z. pseudomonticola and establish possible phylogenetic relationships between the anatomical traits and the near relatives of these species. The leaf material was obtained from living plants and then processed for electron microscopy study.

We found that both species are very similar to each other and to Z. fairchildiana, and that they share several unusual traits with other species of the genus, such as the parenchyma morphology, the spatial distribution of tissues between the veins and the stomata morphology.

The main differences between these species were seen in their fiber clusters and in the abundance of trichome basal cells on the epidermis. The anatomical similarities between the three species could be the result of their close phylogenetic relationship and the divergences between them could be the result of recent speciation during the Pleistocene, resulting from geological changes in Southern Costa Rica.