1963] 



TAXONOMY OF LUZULA SUBGENUS PTERODES 



293 



(Julv 14, 1864) (K); F. Buchenau (Aug. 1, 1883) (US); N. S. Clarice (Aug. 9, 1849) (K) ; 

 B. Gross (July 15, 1931) (US); F. Michalet 125 (K) ; A. B. Paul (July 8, 1905) (GH) ; J. 

 Pfister 1184 (US) ; F. Schultz 624 (GH) ; Thomas (July, 1865) (K) ; F. 0. Wolf 148 (GH, 

 US). YUGOSLAVIA: Cool-, Grubb, Newman $ Whitmore 131 (K) ; Maly (June 20, 1934) 

 (K). 



Hybrids. The only natural occurring hybrid that has been reported is Luzula 

 luzulina X L. pilosa. This hybrid was first reported by Briigger (1880) and 

 later by Murr (1930). In the latter instance it was named L. vinesii. No hy- 

 brids were encountered during the present study. The difference in flowering 

 time between these two taxa would tend to inhibit hybridization, as would their 

 different ecological preference. L. luzulina is restricted to mountainous regions 

 of Central Europe where it usually grows above an altitude of 4,000 feet while 

 L. pilosa is a much wider ranging species generally found at lower altitudes. 

 No other naturally occurring hybrids have been reported, but this species may 

 occasionally hybridize with L. forsteri. 



Luzula luzulina is a very distinct species that is restricted to the high moun- 

 tainous regions of Central Europe (Fig. 4). The long stolons, simple inflores- 

 cence, large flowers, and capsules that exceed the perianth distinguish this taxon 

 from the other two species that occur in this area. All specimens that were ex- 

 amined during this study were collected above 4,000 feet, and generally in 

 coniferous forests or small open areas. 



Before 1906 this species was referred to as Luzula ffavescens since most au- 

 thors were apparently unaware of the earlier name, Juncus luzulina, proposed 

 by Villars (1787). Up to this time the floras and monographs of this genus used 

 the name L. flavescens and many of the earlier collections still bear this name. 

 In addition to the above, a few other names have also been proposed for this 

 species. Desvaux (1808) named this species L. hostii because he considered Jun- 

 cus ffavescens to be inappropriate. He remarks "J'ai cru devoir changer le nom 

 de cette espece, parce qu'elle n'est pas plus jaunaire que la precedente, ni que 

 le suivante." Three other names (L. pallescens, Juncus pallescens, and Juncus 

 pedal us) are either nomina nuda, or were listed as synonyms of L. ffavescens. 



As mentioned previously, artificially produced hybrids between this species 

 and Luzula forsteri resulted in highly fertile F 1 hybrids and F 2 progeny that 

 are sometimes completely fertile. Thus these two species are very closely re- 

 lated, perhaps even subspecies of a single species. However, introgressive hy- 

 bridization studies between these two taxa suggest that hybrids occur rarely, 

 if ever, in nature. This results because of two peculiarities of these species. 

 First, though the ranges of the two overlap, L. luzulina is restricted to the high 

 mountains and alpine regions, usually above 4,000 feet, while L. forsteri grows 

 at much lower altitudes. Secondly, there is a difference in blooming period, 

 with L. forsteri shedding its pollen in April and early May, while L. luzulina 

 usually does not bloom until late May and June. In the other species of the sub- 

 genus Pterodes sterility barriers have maintained the species as separate entities 

 while between these species no sterility barrier appears to exist. In its place is 

 a different ecological habitat and a difference in flowering time that have ac- 

 complished similar results. 



5. Luzula pilosa (L.) Willd. 



Luzula pilosa (L.) Willd. Enum. Hort. Berol. 393. 1809. 



Juncus .pilosus L. Sp. PI. 329. 1753. 



Luciola pilosa (L.) Smith, Engl. Fl. 2: 178. 1824. 



