CYPERACEAE 513 



stage and others in the S (second) stage at the same time ; this brings about dioecism, 

 so that cross-pollination by means of wind can take place very frequently. Besides 

 this, however, small staphylinid beetles, which I frequently found thickly dusted with 

 pollen in the spikelets, seemed to effect cross-pollination. The pollen-grains are pale- 

 yellowish in colour, irregularly tetrahedral to bluntly-triangulo-pyramidal, about 37-5 

 to 43-7 fj. broad and 62-5 jx long. 



In addition to normal flowers with three stigmas, others with two sometimes 

 occur. 



2966. S. Caricis Retz. (=S. compressus Pers.). — In this species the pollen- 

 grains are pale-yellowish in colour, rounded tetrahedral, feebly papillose, 37-5 to 44 n. 

 in diameter. 



2967. S. sylvatlcus L. — This species is strongly protogynous, with persistent 

 stigmas. The stamens do not mature until some days later than the latter. The 

 pollen-grains are yellowish in colour, tetrahedral with small tubercles, about 91 /x in 

 diameter. 



973. Eriophorum L. 



2968. E. polystachion L. — This species is protogynous. The flowers are 

 hermaphrodite or purely female ; specimens with only female ones are often found in 

 sheltered stations. The style of the female flower, bearing 3 long stigmatic branches 

 closely beset with papillae, projects far beyond the bracts. The pollen-grains are 

 sulphur-yellow in colour in the mass, tetrahedral, tuberculate, on an average 37-40 /x 

 in diameter (Warnstorf). 



I. M. Normann (Bot. Not., Lund, 1868, p. 13) states that in the north of Norway 

 this species is sometimes hermaphrodite and dioecious. 



2969. E. vaginatum L. — Raunkjaer says that this species is sometimes com- 

 pletely gynodioecious. 



974. Kobresia Willd. 



Pax describes the spikes as consisting of some two-flowered spikelets, in which 

 the terminal one is male and the lateral female. 



975. Carex L. 



2970. C. dioica L., and 2971. C. Davalliana Sm. — In these species individuals 

 bearing single or more numerous female flowers, at the base or in the middle of the 

 male spikes, are not rare. 



2972. C. baldensis L. — The yellowish-white, capitate inflorescences in this 

 species, formed by the grouping together of the spikelets, are extraordinarily con- 

 spicuous, and undoubtedly attract insects, which effect crossing. At Riva, Appel 

 observed gnats, and a few small beetles. The size of the inflorescence varies greatly, 

 and its conspicuousness is affected by the presence or absence of the largest part of 

 last year's dark-green foliage during anthesis. Appel observed that these conditions 

 varied according to the altitude in the neighbourhood of Lake Garda. 



DAVIS. Ill L 1 



