CAREX FLAVA AND ITS ALLIES— III 



75 



Key to the European species included in C. flava aggregate 



1. Perigynia 4-7 mm. long, arcuate-deflexed with a long attenuate beak. 



2. Female spikes 3-4, upper sessile contiguous, lower sometimes distant and peduncled ; perigynia 



5-25-7 mm., beak 2-2-25 mm. flava 

 2. Female spikes 1-3, somewhat distant, rarely contiguous sessile, lower usually long-peduncled ; 



perigynia 4-5 mm., beak 1-5-1-75 mm. lepidocarpa 

 3. Female spikes short, sub-rotund, with rather few lax spreading perigynia; beak 1-75 mm., 



attenuate. subsp. jenitlandica 



3. Female spikes ovoid, or shortly cylindrical, with rather dense crowded perigynia; beak 

 1-5 mm. 



4. Stems 20-60 cm., rather slender and often curved in fruit; leaves half the length of the 

 fertile stems, narrow, 1-5-2-5 mm. wide; female glumes pale yellow-brown, hyaline, 

 caducous; perigynia 3*5-4 mm. subsp. lepidocarpa 



4. Stems 8-30 cm., stout, rigid, erect in fruit: leaves short, 2-5-4-5 mm. wide; female 



glumes dark chestnut-brown, usually persistent; perigynia 4-5 mm. subsp. scotica 



1. Perigynia 1-4 mm. long, usually straight, or only slightly deflexed, with a short beak. 



5. Stems 20-60 cm. erect; leaves blue-green, less than the length of the stems; lower sheaths red- 

 brown becoming fibrous and sometimes coriaceous. mairii 

 5. Stems 2-30 cm., erect or semi-decumbent; leaves bright yellow-green, more than half the length 

 of the stems; lower sheaths sometimes becoming fibrous, but never coriaceous. 

 6. Stems often curved and semi-decumbent; leaves flat, 3-5-5 mm. wide. demissa 

 6. Stems erect; leaves inrolled, 1-5-2 mm. wide. 



7. Perigynia 3-3-25 mm. long, all but the upper slightly arcuate-deflexed; beak 1 mm. 



dyrrachiensis 



7. Perigynia less than 3 mm. long, straight; beak 0-25-0-5 mm. 



8. Perigynia 1-5-2-25 mm., never inflated; nut completely filling the perigynium; 

 leaves shorter than the stems ; female spikes often separated, seldom contiguous 

 to the shortly peduncled male spike. scandinavica 



8. Perigynia 1-75-3 mm., more or less inflated; nut filling only three-quarters of the 

 perigynium; leaves usually longer than the stems; female spikes usually conti- 

 guous with the sessile male spike. 



9. Plant pale grey-green; stems 5-35 cm., erect; bracts exceeding the inflores- 

 cence, upright; male spike sessile, often female in the middle. viridula 



9. Plant bright yellow-green; stem 2-25 cm., erect; bracts exceeding the in- 

 florescence upright or often spreading; male spike sessile, sometimes 

 female at the base. 



10. Plant 2-20 cm.; male spike always present; perigynia 1-75-2-5 mm. 



serotina 



10. Plant 15-25 cm.; male spike absent or frequently at the top of the 

 uppermost female spike; perigynia 2-5-3*0 mm. 



serotina var. cyperoides 



species descend in height in the following order :- C. lepidocarpa, C. demhsa, C. serotina, 

 C. scandinavica (Plate 7). 



2. Leaves 



The dimensions of the leaves, unlike other vegetative parts of the plant, have prox cd 

 a reliable and a surprisingly constant character, which shows little variation in cultiva- 

 tion. 



(a) Length 



The leaves of C. flava are much longer and broader than those of the other species, 

 and, as in C. serotina, they often exceed the fertile shoots. This is likewise a useful 



