3433 Phippsia (Trin.) R. Br.
- R. Br., Chlor. Melvill.: 27 (1823). - Vilfa taxon Phippsia Trin. in Spreng., Neue Entd. 2: 37 (1821).
Notes: Steen and Elven: The genus Phippsia is morphologically and molecularly close to Puccinellia. Its differential characters are reductions, especially in glumes and in the number of florets (from several to one), and it could be considered a segregate in extreme tundra and snowbed situations. With one exception, all the studied isoenzyme markers found in Puccinellia vahliana also occurred in both species of Phippsia (Steen et al. 2004). The enzymatic differences between Phippsia and Puccinellia vahliana are smaller than often found within species. The near lack of positive enzymatic markers separating Puccinellia vahliana and Phippsia supports a previous proposal to merge the genera (Löve and Löve 1976a). There is, however, a priority matter involved. The name Puccinellia has been conserved, but vs. Atropis and not vs. Phippsia. The name Phippsia has priority before Puccinellia. An inclusion of Puccinellia (several hundred species) in Phippsia (two species) would have nomenclaural repercussions. However, the Löves have already made many of the Phippsia combinations needed for arctic species of Puccinellia. We have decided to retain the genus Phippsia for the Checklist. Both Phippsias are tetraploid. We therefore cannot exclude the possibility that Phippsia is hybridogeneous with one diploid genome from Puccinellia (close to P. vahliana) and one from another source, perhaps Catabrosa or close to that genus. In that case, a stabilization in the direction of one of the parental genera (Puccinellia) must have taken place. A similiar situation is known from Dupontia vs. Arctophila (see above).
Tzvelev: Intergeneric hybrids are common in Poaceae. There is no reason to join Phippsia and Puccinellia.
Steen and Elven: The two species of Phippsia are closely related and have sometimes been considered subspecies. Isoenzymes (Steen et al. 2004) of P. algida and P. concinna were uniform and identical as has been found in a study with other molecular markers (Aares et al. 2000). This is less variation than usually found within a species (and even within a subspecies). The material investigated by Steen included numerous populations each of P. algida, P. concinna, and of what Tzvelev (1971) considered to be their hybrid: P. x algidiformis (see below). All investigated populations were fertile, irrespective of morphology. In a multivariate analysis of morphological data (Steen et al. 2004), there was a nearly continuous variation with the "typical" species located at the opposite ends of the pattern. In univariate analysis, however, numerous characters were found to distinguish well between two and only two taxa. Well developed plants are usually easily identified by several characters in shape of inflorescence, shape and pubescence of glumes and lemmas, and shape of fruit. The two taxa differ in their ecological preferences but with much overlap. They often co-occur but true hybrids (with abortion) have only been documented once in southern Norway and perhaps once in Svalbard. Rank as two species is therefore still merited, both morphologically and 'biologically'.
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Source: Indolences at Wikispecies
