Carex sect. Occlusae, C. B. Clarke

Lu, Yi-Fei, Jin, Xiao-Feng & Yu, Ming-Jian, 2022, Carex borealifujianica (Cyperaceae), a new species of the core Carex clade from Fujian, southeastern China, PLoS ONE (e 0264419) 17 (3), pp. 1-18 : 11-14

Key to the species in Carex sect. Occlusae from China (mainly modified from Flora of China [ 14]).

1a. Spikes approximate, usually aggregated at top of culm, subcapitately disposed; bracts aggregated.

1b. Spikes remote, racemosely disposed; bracts sparsely disposed.

2a. Culms 12–15 cm tall; leaf blade 2–5 mm wide; utricles 2.3–2.5 mm long, ciliate on margins of beak.. ... ... ... ... ... ... ... ... ... .... ... ... ... ... ... ... ... ... .... .1. C. pseudophyllocephala L.K. Dai

2b. Culms 20–60 cm tall; leaf blade 8–15 mm wide; utricles 2.8–3.5 mm long, densely hispidulous.. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .... .2. C. phyllocephala T. Koyama

3a. Pistillate scales connate at base; pistillate spikes with sparse utricles; utricles subrhombic, trigonous, 5–5.3 mm long.. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .... 3. C. poculisquama Kük.

3b. Pistillate scales not connate; pistillate spikes with dense utricles; utricles ovoid or obovoid, obtusely trigonous, 3–4.8 mm long.

4a. Leaf blade 2–4 mm wide; pistillate spikes 3–4 mm wide; utricles sparsely disposed, subdistichous.

4b. Leaf blade 2.5–15 mm wide; pistillate spikes 3.8–6 mm wide; utricles densely disposed, multiseriate.

5a. Staminate spikes 4–7.5 cm long; staminate scales oblanceolate, 7–8.5 mm long; utricles 3–3.6 mm long, glabrous.. ... ... ... ... ... ... ... ... ... ... ... .... ..4. C. nodosa S.R. Zhang et al.

5b. Staminate spikes 1.5–2.5 cm long; staminate scales broadly obovate, 1.5–2 mm long; utricles 3–3.2 mm long, densely hispidulous.. ... ... ... ... ... ... .... 5. C. hebecarpa C.A. May.

6a. Utricles 3–5 mm long, densely hispidulous.

6b. Utricles 3–3.5 mm long, hispidulous on upper margins and veins........9. C. pseudoligulata L.K. Dai

7a. Leaf sheaths not overlapping, sheaths rather loosely enveloping culms; utricles 3.8– 5 mm long.

7b. Leaf sheaths overlapping, sheaths tightly enveloping culms; utricles 3–3.2 mm long-.. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... .... .....7. C. maubertiana Boott

8a. Leaf blade 2.5–5 mm wide, sheaths sparsely pilose; staminate spikes 2 or 3, clavate; achenes emarginate at apex.. ... .... 5. C. borealifujianica Y.F. Lu & X.F. Jin

8b. Leaf blade 5–15 mm wide, sheaths glabrous; staminate spike solitary, cylindrical; achenes acute at apex.. ... ... ... ... ... ... ... ... ... ... ... ... .... 6. C. ligulata Nees