| Calamagrostis sesquiflora (Trin.) Tzvelev | |
| Publ. & Syn. | Tzvelev, Fl. Arct. URSS 2: 74 (1964). - Trisetum sesquiflorum Trin., Bull. Sci. Acad. Imp. Sci. Saint-Pétersbourg 1: 66 (1836). Holotype (LE TRIN-1905.01): Alaska: the Aleutian Islands, "Unalaschka", 1829, leg. Mertens. |
| Notes | Calamagrostis sesquiflora is present in southwestern Alaska but only south of the Arctic. Yurtsev: Calamagrostis sesquiflora differs from C. arctica in, e.g., longer glumes that are more gradually subulate and somewhat reflexed below the tip, and in the awn attached to the lemma in its lower third. Murray and Elven: The characters used by Tzvelev (1964a) and by Yurtsev above for separating C. sesquiflora from C. purpurascens (and from C. arctica) are those often used for separating among species in Calamagrostis. We have studied Alaskan and northeastern Asian material (ALA) of C. sesquiflora and find it distinct from C. purpurascens in several characters: lower leaf surface smooth and shiny vs. dull and scabrous; glumes 8-10 mm and very narrowly lanceolate with very long pointed and arcuately divergent tips vs. up to 7 mm without extended, diverging tips; and awn inserted about 1/3 above base of lemma vs. near base. Other characters for C. sesquiflora are: basal sheaths inflated (not in the others); ligula 1-2 mm and truncate and fringed vs. more than 2 mm; and upper leaf surface roughly short setose (as in C. arctica, soft-pubescent in C. purpurascens s. str.); glumes initially dark purple with a broad golden brown to pale golden hyaline margin vs. more or less uniformly dark purple in C. arctica and pale lilac or pink, in shaded sites almost white, in C. purpurascens s. str.; and awns extending 3-5 mm beyond tip of glumes and arcuate vs. 1-3 mm and straight or geniculate in the others. Anthers are well developed and we assume C. sesquiflora to be sexual. The morphological characters, and the lack of transitional forms in spite of sympatry, support C. arctica, C. purpurascens, and C. sesquiflora as three species. |
| Chromosomes | 28 (4x). - Far East (S, N), Canada (W). - At least five reports. Here we assign also the report of the tetraploid subsp. tasuensis from British Columbia (Taylor and Mulligan 1968). |
| Geography | Amphi-Pacific/Beringian: RFE. |
| Distribution | N = S E = R CE = r [ key ] |
| Parent taxon | Calamagrostis Adans. |
| PAF ID | 342001 |