514 ANGIOSPERMAE—MONOCOTYLEDONES 



2973. C. paradoxa Willd. — This species is sometimes purely male ; such 

 stocks, since their spikelets in later stages are devoid of fruits, have not infrequently 

 occasioned crosses with the hybrids of C. paradoxa Willd., C. teretiuscula Good., and 

 C. paradoxa Willd. or C. paniculata L. Appel says that large sods are often found, 

 of which the inner spikelets are normal composed, but surrounded by a belt of male 

 stems, so that the female flowers are pollinated in whatever direction the wind may be. 



Warnstorf describes the pollen-grains as pale-yellowish-white in colour, tetra- 

 hedral, tuberculate, on an average from 37 /a in diameter. 



2974. C. Schreberi Schrank (= C. praecox Schreb). — Warnstorf describes 

 the pollen-grains in this species as yellowish in colour, spheroidal-tetrahedral, closely 

 beset with small tubercles, about 30 ^ in diameter. 



2975. C. leporina L. — Appel not infrequently observed pollen-collecting 

 insects, especially flies, on the spikelets of this species, which indicates the possibility 

 of entomophily. The varieties argyroglochin Hornem., with its straw-yellow, and 

 atrofusca Christ, with its dark-brown, almost blackish spikes, may also be of 

 oecological significance. 



2976. C. vtilgaris Fries (= C. Goodenowii /. Gay), and 2977. C. stricta 

 Good. — In these species purely male stems occur not infrequently, or spikelets with 

 female flowers becoming male at the tip. 



The pollen-grains are pale-yellow in colour, tetrahedral, with rounded corners, 

 dehcately tuberculate, from 37-43 /a in diameter. (Loew, 'Bliitenbiol. Floristik,' 

 P- 364-) 



2978. C. praecox Jacq. (= C. verna Vill.). — This species, besides C. glauca 

 Scop., is probably one of those in which variations in the position of the spikelets 

 most frequently occur. From the variety gynobasis Spenn., which bears a basal 

 spikelet on a long, slender stalk, there are all transitions to the type in which one 

 terminal male spikelet is present with one to three female ones close below it. 



The pollen-grains are sulphur-yellow in colour, markedly conical to pear-shaped, 

 tuberculate, about 37/1 long and 30 fx. broad. 



2979. C. montana L. — In addition to the most usual form of this species with 

 red-brown spikelets, one with straw-yellow male ones is also frequently found. 



2980. C. digitata L. — The pollen-grains in this species are sulphur-yellow in 

 colour, tetrahedral, tuberculate, 30-7 fx in diameter (Warnstorf). 



2981. C. glauca Murr. — This is one of the most variable German species. 

 Besides the normal female flowers with three stigmas, others with two occur fairly 

 frequently. Appel says that the following forms are also found : — 



(i) A single terminal male or female spikelet ; 



(2) A basal long-stalked female spikelet, otherwise normal; 



(3) All female spikelets with short stalks and distributed over the upper two-thirds 

 of the stem ; 



(4) Female spikelets with long stalks, hanging over when the fruit ripens, and 

 inserted more or less widely apart; 



(5) Female spikes are either all, or the terminal one only, male at the tip ; 



