Scribneria

Röser, Julia Schneider Grit Winterfeld Martin, 2012, Polyphyly of the grass tribe Hainardieae (Poaceae: Pooideae): identification of its different lineages based on molecular phylogenetics, including morphological and cytogenetic characteristics, Organisms Diversity & Evolution (New York, N. Y.) 12 (2), pp. 113-132 : 125-126

Scribneria ( lineage III )

The placement of the monotypic genus Scribneria (only S. bolanderi ) in a lineage together with Deschampsia cespitosa is obtained by cp mat K as well as nuclear ITS (Figs. 1 and 2). Additionally, a 3 bp deletion in the intron region between the mat K gene and the 3′ trn K exon supports the close relatedness of both taxa. CpDNA restriction site data have shown Scribneria to be distant from the traditional Hainardieae genera Hainardia , Parapholis and their relatives, and placed in a clade with Aira , Avenula , Holcus , and Molineriella

Scribneria bolanderi have a tough rachis and spikelets disarticulating below each floret. f Pholiurus pannonicus with tough rachis and spikelets falling entire. Material used: a fruits from Göttingen Botanical Garden in 2006, no. 1850 (HAL); b Werner 3477 (HAL 71657); c Rivas-Martínez s.n. (BASBG); d left Kralik s.n. (JE), right Cosson s.n. (JE); e left Wilken 16163 and Painter ( RSA 695253), right Ahart 10180 ( RSA 692211); f Hilbig s.n. (HAL 67272)

( Soreng and Davis 2000). Unfortunately, the close relatedness of Scribneria and Deschampsia remained unnoticed in that study, because what the authors considered Deschampsia cespitosa had been misidentified material of Agrostis (Davis and Soreng; 2007: p. 347). Placement of Deschampsia in Clade 2 ( Poeae ; Figs. 1 and 2) is now firmly established by cp and nuclear DNA data ( Davis and Soreng 2007; Döring et al. 2007; Quintanar et al. 2007; Bouchenak-Khelladi et al. 2008; Döring 2009; Schneider et al. 2009; Saarela et al. 2010).

Maintenance of a separate monotypic Scribneriinae for Scribneria ( Soreng et al. 2003; 2007) is not required, due to the sister relation to Deschampsia revealed by the molecular data (Figs. 1 and 2). We suggest that both genera be accommodated in a common subtribe, because Scribneria having an awned lemma with a hairy callus ( Table 3; Figs. 3e and 4g, h ) resembles Deschampsia also morphologically as noted by Stebbins and Crampton (1961). Additionally, Scribneria does not always have spicate to racemose inflorescences. Inflorescences of vigorous specimens are reduced panicles with several branches at the lower nodes and comparatively long-pedicelled spikelets on partly branched peduncles (personal observations; Stebbins and Crampton 1961; Smith 2007). A close relation of Scribneria and Deschampsia is reflected also in the occurrence of 2 n 0 26 chromosomes ( Table 4, Figs. 1 and 6a) based on a monoploid chromosome number of x 0 13, which is rather uncommon within the whole subfamily Pooideae .

The precise placement of the genus pair Deschampsia / Scribneria ( lineage III in Figs. 1 and 2) within Clade 2 ( Poeae ) should be investigated further with a more extended sampling of additional Clade 2 taxa. From previous investigations, albeit using a different sample of genera than ours, it is obvious that Deschampsia cespitosa and other species of Deschampsia s.str. are close to Holcus and Vahlodea and rather distant from Aira and Avenella (cpDNA: Döring et al. 2007; Quintanar et al. 2007; Soreng et al. 2007; Döring 2009; Schneider et al. 2009; Saarela et al. 2010; nuclear DNA: Schneider et al. 2009). Alternatively, Deschampsia was slightly distant also from Holcus and Vahlodea , but even more distant from Aira and Avenella (cpDNA: Davis and Soreng 2007; nuclear DNA: Quintanar et al. 2007) or Deschampsia , Avenella and Holcus were part of more or less a polytomy ( Saarela et al. 2010).

In view of the available molecular phylogenetic information (cf. also Garcia-Suárez et al. 1997) merging of Deschampsia with Aira , Avenella and other genera under subtribe Airinae thus should be discontinued. Further study is necessary to ascertain if the two genera Deschampsia and Scribneria represent together a separate subtribe; in this instance, its correct name would be Aristaveninae (cf. Albers and Butzin 1977) due to nomenclatural priority over Scribneriinae . Conversely, if Deschampsia and Scribneria are placed together with Holcus and Vahlodea in a common lineage, the older subtribe name Holcinae would be applicable.

Figures

Fig. 4 a–h Spikelet details. Palea of a Hainardia cylindrica and b Parapholis incurva with glabrous keels (nerves). c, d florets of Narduroides salzmannii with glabrous callus of the lemmas and long rachilla internodes. e, f Agropyropsis lolium with glabrous callus of the lemma (e) and ciliolate keels of the palea (f). g, h Scribneria bolanderi with lemma awned from a sinus of the lemma tip (g) and hairy callus (h). The margin of the lemma is marked at one side in a, b, and f with arrows. Material used: a fruits from Göttingen Botanical Garden in 2006, no. 1850 (HAL); b Röser 2517 (HAL); c Hernández s.n. (C); d Rivas-Martínez s.n. (BASBG); e, f Cosson s.n. (JE); g, h Wilken 16163 and Painter (RSA 695253)