KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 55- NIO 5. 



213 



species respecting the interlacunar cortical bundles which often occur in two circles 

 or in one complete ligular circle and one incomplete one vvithin it, whereas P. gra- 

 mineus always has only one (the ligular) and P. lucens alvvays (2 — ) 3. Subepider- 

 mally there are scattered strands. The endodermis- 

 cells sometimes present the lucens-type, sometimes 

 the more compressed type characteristic of P. gra- 

 mineus. The arrangement of the central bundles 

 corresponds with that of the two parent-species. 



In order to get a synopsis of the many 

 forms, the Fiberian arrangement of the year 1838 

 can still be maintained with the closer definition 

 I ha ve made in Neuman, Sveriges Flora, 1901, 796. 

 It is namely apparent that the middle internodes of 

 every form has a tendency to elongate themselves, 

 whereas the upper ones seem to present more con- 

 stancy. 



Var. a validus Fieber: Internodia omnia aut 

 saltem superiora tria sub spica primaria breviora, 

 30 — 60 mm, vel infra. Folia suprema interdum na- 

 tantia vel subcoriacea. 



To this form-series ought to be reckoned: 



f. lucescens (Tis.) Hagstr. P. lucens p luce- 

 scens Tis., 1. c. no. 59: — Folia caulina magna, 

 20 — 25 mm lata, omnia breviter petiolata. Stipulse 

 breviores et magis quam in P. lucente caducae. 



This form passes över into f. foliosus which, 

 however, has longer internodes and nearly sessile 

 and still larger stem-leaves. The ligules always 

 show influence from P. gramineus. 



f. loilgipetiolatllS (TlS.) HAGSTR. P. luceriS '{ Fig. 103. P. Zizii M. & K. A, Involucral 



7 , . 7 ,-p, . nr . i a 4 ' ea f 0I forma lucentifonnis Hagstr., j, from locus 



longipeholatUS I IS. 1. C. nO. 60, non no. 144: classicus: Sudermania in lacn Mäskaren ad Fred- 



Folia superiora longe petiolata. LigulcE magis per- Jf Z^^V^t^T^i^T, 



SistenteS. specimen from Long Drove, Pidly Fen, Hunting- 



donshire, England, 88, Fryer no. 1188, showing 



LeaveS aS in the precedeilt, but at (under and an extremely rare instance of reduced lamina, 



> . , . .1 /. .i . i i- \ aceording to what often is the case in P. lucens. 



o ver) the pnmary spike (in the stem-elongation) The red uction bas hen fallen on the to P , whe- 

 long-petioled (influence from P. gramineus), petioles f ea f s " ie f base has its . us ^ al sh& vp }■ <\ stem- 



»I v J '' tr leaf of forma commums Hagstr. from Sieily, the 



never longer than the blades, though, usually shor- » R licens* l. psiiostaehyum tik.», described by 



° ' & ' J tineo, ;. 



ter. Ligules longer persistent, i. e. more lucens-like. 



The topmost leaves sometimes have nearly subcoriaceous structure (from gramineus). 



f. lucentifonnis Hagstr.: Folia caulina omnia sat longe petiolata, magna, 25 — 

 30 mm lata. Ligulse fere ut in P. lucente. Fig. 103, A. 



The most lucens-like of all Zizii-iorms by its large, petioled leaves, and durable 

 stipules. The branch-leaves, the apexes of the upper leaves, and the ramification of 



