FNA: Luzula vs. Luzula subg. Luzula

Distribution

Temperate and arctic regions worldwide; tropical mountains

Temperate and arctic regions and tropical mountains

Discussion

The leaves of Luzula are primarily basal; cauline leaves are usually reduced.

Luzula species have diffuse centromeres and small chromosomes. That has resulted in much confusion in interpretation and reporting of chromosome counts. No attempt has been made to include reported counts that could not reasonably be verified by the author.

Excluded species: Luzula sudetica (Willdenow) de Candolle. Although reports of this European species appear frequently in the North American literature, I have seen no specimens that confirm its presence. No chromosome counts are published for North American material. Since this species has a distinct cytotype, 2n = 48 (H. Nordenskiöld 1956), it should not be difficult to verify on this basis.

Species ca. 108 (23 in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Species ca. 50 (15 species in the flora).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key

1. Flowers in dense clusters (glomerules); inflorescences spikelike or umbellate; seeds with caruncle conspicuous to barely visible	subg. Luzula
1. Flowers solitary or in small clusters of 2–4; inflorescences mostly unbranched or dichasial; seeds with caruncle conspicuous to absent.	→ 2
2. Flowers solitary; inflorescences corymbose, rarely branching; seeds with caruncle conspicuous	subg. Pterodes
2. Flowers mostly in pairs, rarely in clusters of 3–4, or solitary; inflorescences paniculate or dichasial; seeds with caruncle inconspicuous or absent	subg. Anthelaea

1. Inflorescences dense, spikelike, though often interrupted, nodding	L. spicata
1. Inflorescences of distinct glomerules, not spikelike, sometimes lax but not nodding.	→ 2
2. Inflorescences of sessile glomerules only or with smaller glomerules on short branches.	→ 3
2. Inflorescences with central glomerule(s) sessile or nearly sessile, always with other pedunculate glomerules.	→ 8
3. Proximal inflorescence bract conspicuous, usually well-exceeding inflorescence.	→ 4
3. Proximal inflorescence bract inconspicuous.	→ 7
4. Seeds 1.3 mm, caruncle absent.	L. subcapitata
4. Seeds 0.8–1.5 mm, with caruncle.	→ 5
5. Seeds 0.8 mm, caruncle 0.2 mm	L. orestera
5. Seeds 0.9–1.5 mm, caruncle either barely visible or at least 0.3 mm.	→ 6
6. Capsules ovoid; caruncle barely visible.	L. groenlandica
6. Capsules spheric; caruncle 0.3-0.8 mm	L. comosa
7. Tepals shorter than capsule; bracteoles deep brown, dentate	L. arctica
7. Tepals and capsule about equal; bracteoles clear to deep brown, conspicuously fimbriate	L. confusa
8. Inflorescence branches straight.	→ 9
8. Inflorescence branches arching.	→ 14
9. Inflorescence branches mostly erect; glomerules mostly cylindric.	→ 10
9. Inflorescence branches divergent as much as 90°; glomerules not cylindric.	→ 12
10. Tepals pale or with brown central area at maturity; seeds 0.7–1 mm; caruncle 0.2–0.3 mm	L. pallidula
10. Tepals pale brown to chestnut brown to blackish at maturity; seeds 0.9–1.7 mm; caruncle 0.2–0.7 mm.	→ 11
11. Seeds 1.1–1.7 mm; caruncle 0.2–0.6 mm	L. multiflora
11. Seeds 0.9–1.3 mm; caruncle 0.5–0.7 mm	L. bulbosa
12. Leaves with callous apex; glomerules sessile to congested to spreading.	→ 13
12. Leaves without callous apex, glomerules on elongate peduncles	L. echinata
13. Stolons slender and short, conspicuous rhizomes present	L. campestris
13. Stolons or conspicuous rhizomes absent.	L. comosa
14. Inflorescence branches arching in all directions; basal leaf sheaths bluish green	L. subcongesta
14. Inflorescence branches arching in 1 direction; basal leaf sheaths variously colored.	→ 15
15. Basal leaf sheaths dull brown-gray to green; cauline leaves as large or larger than basal leaves	L. kjellmaniana
15. Basal leaf sheaths shining reddish to brown to purple; cauline leaves usually smaller than basal leaves.	→ 16
16. Basal and cauline leaves not reaching inflorescence	L. arcuata subsp. unalaschkensis
16. Basal and especially cauline leaves often reaching or exceeding inflorescence	L. confusa