CYPERACEAE 511 



spikelets, in which, however, both sexes are arranged variously ; it is divided into 

 three groups, e.g. Acrarrhenae, in which all the spikelets are male at the tip and 

 female at the base ; Hyparrhenae, with male spikelets at the base and female at the 

 tip ; and Holarrhenae, in which the middle spikelets are male, while the terminal and 

 basal ones are female. 



Here also we find a great tendency to variation, particularly in the last group 

 with its species of C. disticha Huds., C. arenaria L., and C. pseudo-arenaria. The 

 division of the sexes is not only found in quite different parts of the spikeiet, in which 

 first one then the other sex predominates ; but the relative position of the sexes may 

 also vary. 



Finally the group of Heterostachyae includes those species which typically 

 possess one or several terminal male spikelets and several lateral female spikelets. 

 C. Buxbaumii Wahlenb. is also reckoned in this group, as it bears female flowers at 

 the tip of the male spikeiet. This arrangement is, however, not infrequently found 

 in other species also, e.g. in C. glauca Scop. But the reverse, i.e. terminal spikelets 

 which are female at the base, are not rare. The female spikelets very frequently 

 contain a number of male flowers, sometimes at the tip (especially frequent in 

 C. glauca Scop., and sometimes at the base, as in C. vulgaris Fries, or distributed 

 over the whole spikeiet. 



Compound spikelets are also not rare, and are particularly frequent in C. sylvatica 

 Huds. and C. glauca Scop. 



The number of stigmas, which is also considered in systematics, is not quite 

 constant. In species normally bearing three stigmas flowers are not infrequently 

 found bearing only two, e.g. C. paludosa Good, and C. glauca Scop.; on the other 

 hand, though more rarely, styles with three stigmas (e. g. in C. acuta L) are found in 

 spikelets of species with two stigmas. 



Speaking generally, therefore, the distribution of sexes in the genus Carex is on 

 the one hand very numerous, but on the other hand very variable. 



A fact connected with the process of fertilization, but not yet satisfactorily 

 explained, may also be mentioned. Completely or partially sterile axes and stocks 

 are often found, which are not hybrids. I observed this to be particularly striking 

 in C. glauca Scop, at Winterthur, C. vesicaria L. in the Binninger Rind (South 

 Baden), C. panicea L. at WUrzburg, and other species in a more or less marked 

 degree. The assumption seems jusdfied that such occurrences may be explained 

 by the absence of fertilization in consequence of unfavourable weather in species 

 dependent on dryness and wind for pollination. 



Andersson and Hesselman (' Bidrag till Kanned. om Spetsbergens o. Beeren 

 Eil. Karlvaxtflora,' pp. 77-82) observed the flowering and fruiting times of the 

 following species in Spitzbergen. — Carex saxatilis Z., C. misandra R. Br., C. salina 

 Wahlenb. var. subspathacea Drej., C. vulgaris Fries (= C. rigida Good.), C. ursina 

 Dewey, C. lagopina Wahlenb., C. glareosa Schkuhr, C. incurva Light/., C. dioica L. 

 var. parallela Laest., C. nardina Fries, C. rupestris AIL, Eriophorum anguslifolium 

 Roth var. j8. triste Fries, E. Scheuchzeri Hoppe. 



Vanhoffen (Abromeit, ' Bot. Ergeb. von Drj'galski's Gronlandsexped.,' pp. 85-95) 

 observed the following species flowering and mostly fruiting in Greenland during June 

 to August. — Eriophorum Scheuchzeri Hoppe, E. polystachion L., Kobresia caricina 

 Willd., Carex nardina Fries, C. capitata L., C. scirpoidea Michx., C. microglochin 

 Wahlenb., C. rupestris All., C. incurva Light/., C. glareosa Schkuhr, C. bicolor AIL, 



