Most of the features used to classify species in the order Fucales at the generic level are morphological, and the diagnostic features are based on the number of eggs produced per oogonium (Ohno et al. 1995, Cho et al. 2006): four in
Anatomical knowledge about
Plants were collected in 2003, 2004, and 2005 from three sites in each of three localities along the southwest-ern Gulf of California: San Juan de la Costa (24°19'34" N and 114°34'10" W), Punta Calera (24°21.0' N and 114°16.0' W ), Punta Machos (26°6′20″ N and 111°18'30" W). At each site, 30 plants with several fronds each were randomly se-lected for morphological and anatomical analyses.
Samples were embedded in 4% formaldehyde and sea water. All material collected was used to analyze the vegetative (cauline) and reproductive (receptacles) struc-tures and the variability in these structures within fronds. Fifteen receptacles were taken from each frond and pro-cessed by histological techniques.
Ninety samples were collected from the southwestern Gulf of California and preserved in 4% formaldehyde and sea water. A total of 45 thalli with receptacles were cho-sen, and twelve receptacles were taken from each thallus; all of the specimens were labeled with the date and loca-tion. We selected a group of specimens after dehydration in an alcohol series (30, 60, 90, and 100%) and butane for
30 minutes each. After we embedded the tissue in paraf-fin-butane and paraffin, we prepared 10 μm sections that were mounted permanently.
The anatomical analysis showed that the basal part of the thalli contained a real cauline with three tissue lay-ers (Fig. 1). These layers were maintained over the stipe where a thicker cortical area and a wide medullar section were present in all samples. The upper part of the stipe showed a significant increase in width with cell layering, additionally, the holdfast showed the epithelial and cor-tical cells (Fig. 2). The blade cross section revealed epi-thelial cells, medullar cells, and trumpet cells (Fig. 3). The cryptostomata was composed of epithelial cells, cortical cells, medullar cells and paraphyses, and these structures were different than those of antheridial cells. Epithelial cells, cortical cells, and a blank space were found in the longitudinal bladder section (Fig. 4).
We found that the thallus receptacle structures looked like a
[Fig. 2.] (A) Stipe cross section: epithelial cells (e), cortical cells (c), medullar cell (m). (B) Holdfast cross section: epithelial cells (e), cortical cells (c). Scale bars represent: A & B, 200 μm.
[Fig. 3.] (A) Blade cross section: epithelial cells (e), cortical cells (c), medullar cells (m). (B) Blade longitudinal cut: cortical cells (c), trumpet cells (t). (C) Close up of trumpet cells (t), cortical cells (c). Scale bars represent: A-C, 200 μm.
[Fig. 4.] (A) Cryptostomata anatomy: base of the capsule (a), paraphises (p), pore (r). (B) Bladder cross section: capsule (b), cortical cells (c). (C) Male conceptacle: paraphises (p), base of the conceptacle (f), antheridia (h). (D) Conceptacle with zygote (d), mature oogonium (o), antheridia (h). (E) Mature conceptacle: paraphises (p), pore (r). Scale bars represent: A-D, 200 μm.
but with a disc-shaped gelatinous plug (Fig. 5).
This species has a cylindrical receptacle in which many conceptacles were present. We found female and male caps in sections from the same receptacle and occasion-ally we found oogonium and antheridial cells within the same conceptacle; antheridia have a pedicel over the conceptacle wall. In contrast, the oogonium and anther-idia were in the same conceptacle. Additionally, we could see the paraphises near the pore, and the nucleus of the oogonium.
Norris (2010) reviewed the taxonomy of the genus
in our study, we found them together, making it impos-sible to use this character to delimit the species. Gillespie and Critchley (1997) reported that the morphology of the receptacle should be different between species, and, moreover, that these differences are affected by time and the habitat in which the thallus was found. They report-ed that when thalli live in the surge zone, the receptacle has to be more branched than if the plant lives in quiet waters, and if this receptacle characteristic is combined with short blades then the level of fertilization would increase. Additionally,
The present study confirmed the presence of caulines in this species, a structure that has previously been de-scribed in some species from the Gulf of California, such as