Ampelodesmos mauritanicus (Poir.) T. Durand & Schinz, 1894

Vázquez, Francisco Maria, Márquez, Francisco, García, David & Oualidi, Jalal El, 2025, A taxonomic revision of Stipeae s. l. tribe (Poaceae) in N Africa, Phytotaxa 699 (1), pp. 1-174 : 117-121

Ampelodesmos mauritanicus (Poir.) T. Durand & Schinz ( Figure 67 ).

Lemma dorsal surface: Characterised by rectangular long cells of (30–)50–80(–90) × 10–12(–14) µm, sinuous walls up to 7 µm thick, linear distribution. Short cells: main Silica cells (10–)12–14(–16) × 10–12 µm, circular to ovoid, frequent, solitary or with hooks, occasionally with cork cells, in pairs or threes between long cells, density (8–)10–12(– 14) silica cells/100 µm 2; Cork cells (3–)5–10 × 8–10 µm, fusiform to reniform, sporadic, in all cases with silica cells. Spines and hairs: Hooks ovoid to circular base (18–)20–30(–32) × 9–16(–18) µm high, irregularly distributed between long cells, in pairs or threes with silica cells, cork or additional hook cells, frequently solitary, density 6–12 hooks/100 µm 2); Prickles not studied; Macro-hairs not studied.

Lemma apex surface: Characterised by long cells similar to those of the dorsal area. Short cells: Silica cells of equal size, distribution, density and morphology to those of the dorsal area; Cork cells of equal size, and distribution to the dorsal. Spines and hairs: Hooks of equal size, morphology, and density to dorsal; Prickles circular to ovoid base 18–29(–32) × 16–25(–30) µm and up to 85 µm long, distributed at middle of apex, density 7 prickles/100 µm 2; Macro-hairs of circular to obovate base 25–35(–37) × 20–28(–30) µm and up to 160 µm long, located at distal part of apex and the appendix.

Material studied: Morocco: Tamsamane, 210 m. a.s.l., 5-V-2022, M . Chamboleyron , ECWP n.n.; Zaida , 1570 m.a.s.l., 15-V-2018, M . Chamboleyron , ECWP n.n.

Numerical taxonomy results

The results obtained for each of the analyses carried out are presented the following sections: micromorphological characters; macromorphological characters; overall analysis with all characters.

Micromorphological Characters

In the figure above it is possible to identify five clades in which all the taxa included in the study are grouped. Each of these clades is identified by the letters A, B, C, D, E, and in each of them includes groups in which a single genus is recognised, as in Clade E ( Macrochloa ), Clade D ( Stipa ), Clade A ( Achnatherum ) and Clade C ( Ampelodesmos ), while Clade B includes the remaining four genera studied ( Celtica , Oloptum , Piptatherum and Stipellula ) (see Figure 68 ).

In this first analysis the results offer two major divisions within the Stipeae : those that include Stipa and Ampelodemos and the group that includes the rest of the genus.

The results of the analysis of the micromorphological characters of the lemma allowed the separation of a good number of the genera of the Stipeae in the N of Africa.

Based on the micromorphological characters of the lemma, the separation of the species within each of the genera is low: section-level separation has only been observed in Stipa and between species in genera such as Achnatherum and Stipellula .

Macromorphological Characters

The results of the analysis of the macromorphological characters partially coincide with those of the analysis of the micromorphological characters of the lemma ( Figure 69 ):

Five clades were identified.

There are three clades that can be identified by combining a single genus: Clades C ( Ampelodesmos ), D ( Stipa ), and B ( Stipellula ).

Clade E includes representatives of Celtica and Macrochloa , while Clade A includes together representatives of several genera: Achnatherum , Oloptum , Piptatherum and Stipellula .

The results of this analysis allowed a better differentiation of the taxa studied and the sections of the genus Stipa were separated again.

Global analysis of Micromorphological plus Macromorphological characters

As in the previous analyses, the results of the analysis of the sum of all the characters examined appeared in five clades. There are clades that systematically repeat the pattern of representing a single genus as in the case of clades C ( Ampelodesmos ) and D ( Stipa ), in addition to the inclusion of Clade E ( Macrochloa ), previously differentiated in the micromorphological analysis ( Figure 70 ).

Clades A and B again show results where several genera can be grouped. Clade A includes representatives of the genera Achnatherum , Oloptum , Piptatherum and Stipellula p.p., corresponding to Clade A proposed after the analysis of macromorphological characters, and Clade B includes taxa of the genera Celtica and Stipellula p.p ..

The previously indicated results are confirmed as it is possible to separate sections within the genus Stipa where the taxa studied can be easily discriminated in most cases.

Additional analysis of Clades A and B

The analyses carried out discriminating micromorphological and macromorphological characters of the lemma, and an overall analysis of all characters, have revealed a group of genera in Clades A and B with high levels of similarity but differences in distribution. For this reason, a separate analysis of these taxa was carried out, incorporating the total characters studied and introducing Clade E as an element showing high level of difference between these taxa ( Figure 71 ).

The analysis of Clades A and B together with Clade E, shows a clearer separation of some of the taxa and it is possible to discriminate the genera Achnatherum , Celtica and Macrochloa homogeneously and with more than 0.3 units on the established scale.

The genera Piptatherum and Oloptum remain in the same clade and only P. fumeauxii shows a clear distance from the rest of the taxa. Stipellula maintains the trend of previous analyses, where S. parviflora is found in the Achnatherum , Piptatherum , Oloptum clade, while the rest of the taxa of Stipellula are grouped in the Celtica Clade. This analysis allowed a clearer separation of almost all species involved.

Figures

FIGURE 67. Lemma surface of Ampelodesmos mauritanicus. A. Lemma central dorsal surface view. B. Lemma margin dorsal surface view. C. Lemma apex. lc. Long cell. sc. Silica cell. cc. Cork cell. h. Hook. p. Prickle. mh. Macro-hair. Bars indicate 100 µm.

FIGURE 68. Dendrogram showing the degree of similarity based on analysis of the Cluster UPGMA method, in micromorphological characters (SEM) of the lemma for studied taxa of the Stipeae and Ampelodesmeae from N Africa. The taxa appear variously coloured depending on their generic framing:orange (Achnatherum P.Beauv.); light green (Celtica F.M.Vázquez & Barkworth); brown (Macrochloa Kunth); red (Oloptum Röser & Hamasha); purple (Piptatherum P. Beauv.); blue (Stipa L.); pink (Stipellula Röser & Hamasha); dark green (Ampelodesmos Link). Similarity index: Gower. Contrasts: Groups. Computer Boot N: 5. Cophen. Corr.: 0.9228. Similarity matrix: Gower (index appendix Ia).

FIGURE 69. Dendrogram showing the degree of similarity based on analysis of the Cluster UPGMA method, in macromorphological characters for studied taxa of the Stipeae and Ampelodesmeae from N Africa. The taxa appear variously coloured depending on their generic framing (see Figure 68). Similarity index: Gower. Constraints: Groups. Computer Boot N: 5. Cophen. Corr.: 0.9034. Similarity matrix Gower index appendix Ib.

FIGURE 70. Dendrogram showing the degree of similarity based on Cluster UPGMA analysis, supported by the micromorphological characters (SEM) of the lemma together with the macromorphological characters for studied taxa of the Stipeae and Ampelodesmeae from N Africa. The taxa appear in different colours according to their generic framing (see Figure 68). Similarity index: Gower. Constraints: Groups. Computer Boot N: 5. Cophen. Corr.: 0.9365. Similarity matrix Gower index appendix Ic.

FIGURE 71. Dendrogram showing the degree of similarity based on analysis of the Cluster UPGMA method, supported by micromorphological characters (SEM) of the lemma together with macromorphological characters for any studied taxa of the Stipeae from N Africa. The taxa appear variously coloured depending on their generic framing (see Figure 68). Similarity index: Gower. Constraints: Groups. Computer Boot N: 5. Cophen. Corr.: 0.9991. Similarity matrix Gower index appendix Id.