Luzula forsteri subsp. rhizomata (Ebinger) Z.Kaplan
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Authority
Ebinger, John E. 1964. Taxonomy of the Subgenus Pterodes, Genus Luzula. Mem. New York Bot. Gard. 10 (5): 279-304.
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Family
Juncaceae
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Scientific Name
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Description
Latin Diagnosis - A var. forsteri rhizomatibus 2-4 cm longis; caulibus 20 cm altis; laminis foliorum caulinorum 2-4 mm longis differt.
Species Description - This variety is similar to variety forsteri, but differs in that rhizomes are present. These are to 4 cm long and 2 mm in diameter. The plant is 20 to rarely 30 cm tall, and the culm leaves do not exceed 4 cm in length and 1-2 cm in width. This variety is restricted to the eastern Mediterranean Region (Fig. 2).
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Discussion
Type. Davis 21536: Turkey, Cankiri Providence, Ilgav District, Yaylacik; 1000 meters in Pinus nigra forest; June 5, 1954. (K.)
Hybrids. None have been reported and none were found during this study.
Luzula forsteri is a wide ranging species that is very distinct and easily distinguished from any other member of the subgenus. Morphologically it is more closely related to L. plumosa, from which it differs in the lack of a large hooked caruncle on the seed, and the presence of a mucro on the callose tip of the leaf.
Experiments by Nordenskiold indicates that genetically L. forsteri is most closely related to L. luzulina. The Fi hybrids produced were 80 to 90 percent fertile and some of the Fo progeny were 100 percent fertile. Present information, however, indicates that these two species do not hybridize in nature. This lack of hybridization is due to a difference in blooming period and ecological conditions that will be discussed more fully under L. luzulina.
The only other species which occurs in the same general region and with which Luzula forsteri would have an opportunity to hybridize in nature is L. pilosa. Both of these species are found in Europe, but L. pilosa generally occurs farther north. These species do come into contact, however, and some hybridization takes place. Fi hybrids between these two species are completely sterile, according to Nordenskiold's experiments, but Ebinger (1962a) found that this hybrid occasionally sets a few seeds and that it may backcross with one of the parents.
The material that is now considered Luzida forsteri was combined with Juncus pilosus (= L. pilosa) until 1804. Once it was recognized as being specifically distinct, however, this concept was accepted by most botanists. Most of the names attributed to this species are transfers to other genera that are now considered synonyms of Luzida. In a few cases, however, the names are later described synonyms (L. decolor and L. gesneri) or herbarium names (L. barrelieri) that were introduced into the literature as synonyms of L. forsteri.
Although the variety forsteri is relatively constant in its characters, many of the specimens from Spain, Portugal, northwest Africa and the Canary Islands have culm leaves that are wider than is usual for members of this variety. Plants with this characteristic have been referred to as Luzula decolor by earlier authors. The variety pallida, which is here considered a synonym of L. forsteri var. forsteri, was described as having flowers that are pale yellow in color. This condition was sometimes found, but seems not to be correlated with a particular locality, but rather represents the normal variation of the species. Variety rhizomata, in contrast, has a distinct geographic range, and is easily separated from variety forsteri by the presence of rhizomes.