552 CYPERACEAE 



C. acutiformis is one of our most variable sedges ; one of the modifica- 

 tions is that in which the glumes of the female flower are terminated 

 by a long rough awn which exceeds the perigynium. This, the var. 

 spadicea (Roth, Tent. Fl. Germ. 2, ii. 461, as a species), C. Kochiana, 

 DC. Cat. Hort. Monsp. 8, has been noticed in all the districts, as 

 at Wytham, Eynsham, plentifully by the Marcham Canal, near Pang- 

 bourn, plentifully along tlie Kennet Canal, and by the Loddon and 

 Thames. It is not unlikely that hybrids of C. acutiformis, with 

 C. riparia and perhaps C. acuta, are grouped under it. since, when the 

 fruit is imperfect, the glume often becomes of disproportionate size. 

 The length of the glume in this and other sedges is very variable, and 

 I do not myself consider it sufficient in itself to be a mark of varietal 

 distinction. 



Near Marcham I gathered a plant which is almost certainly 

 C. acutiformis x riparia. 



In Frilford Marsh I found a sterile form which rather suggested 

 a trace of C. roslrata. By the Loddon some very luxuriant plants were 

 seen with, paler perigynia than usual. 



A plant which I saw by the Thames near Iffley in 1883 suggests 

 a hyjjrid with C. acuta ; it is too ripe to see the number of stigmas, but 

 the fruit, although much more flattened than C. acutiformis in its 

 typical state, has a longer beak than that of C. acuta. 



By the Kennet I have also gathered the /. digyna, and another form 

 with very distant and shorter spikes. The forma composita, with one or 

 more small spikes at the base of the lower spikes, has been noted at 

 Marcham and near Newbury. Specimens with the lower male spikes 

 bearing a few female flowers are not uncommon ; such have been seen 

 at Virginia Water, and by the Thames and its tributaries. A plant 

 which occurred by the Wantage Canal, with very short and partly 

 sterile spikes, Mr. Arthur Bennett tells me, is near to the plant called 

 C. paludosa, var. depauperata, Lange. 



C. acutiformis occurs in all the bordering counties. 



C. riparia, Curt. Fl. Lend. iv. t. 60 (c. 1783). 



C. crassa, Ehrh. Beitr. iv. 43 (1789). C. vesicaria, Leers, Fl. Herbon. 

 t. 16, not of Linn. 



Top. Bot. 471. Syme, E. B. x. 167, t. 1689. Nyman, 767. Fl. Oxf. 322. 



Native. Paludal. On the margins of rivers, canals, ditches, ponds, &c., 

 in marshes, &c. Abundant in all the valleys of the county, but 

 reaching its maximum of frequency on the Thames, where it is 

 a very conspicuous feature in the vegetation, and is frequently 

 represented in pictures of that river. The contrast of its 

 glaucous-coloured leaves and the glossy brow^n glumes and yellow 

 anthers is pleasing. P. May-June. 



