KUNGL. SV. VET. AKADEMIBNS HANDLINGAE. BAND 55. N:0 5. 



213 



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

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

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

 mally there are scattered strands. The endodermis- 

 cells sometimes present the liicens-type, sometimes 

 the more compressed type characteristic of P. gra- 

 7nineus. 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 have 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 tiia 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. Iiicescens (Tis.) Hagstk. P. lucens p luce- 

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

 20 — 25 mm lata, omnia breviter petiolata. Stipulaj 

 breviores et magis quam in P. lucente caducse. 



This form passes over 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. longipetiolatus (Tis.) Hagstr. P. hicens 7 

 longipetiolatus Tis. 1. c. no. 60, non no. 144: — 

 Folia superiora longe petiolata. Ligulce magis per- 

 sistentes. 



Leaves as in the precedent, but at (under and 

 over) the primary spike (in the stem-elongation) 

 long-petioled (influence from P. gramineus), petioles 

 never longer than the blades, though, usually shor- 

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

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



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

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



The most lucens-\ike of all Zizii-iovms by its large, petioled leaves, and durable 

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



Fig. 103. P. Zizil Jrl. & K. A, Iiivolucral 

 leaf of forni.a Iitcen/iforinis Hagstd., J, from locits 

 cJas.'ficics/ Sndermaniii in lacn Mjisltaren ad Fred- 

 riksnas; showing the relation between the length 

 of the petiole and the apex. B, Stem-leaf of a 

 specimen from Long Drove, Pidly Fen, Hunting- 

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

 an extremely rare instance of reduced lamina, 

 according to what often is the case in P. lucens. 

 The reduction has here fallen on the top, whe- 

 reas the base has its usual shape, ]. C, Stem- 

 leaf of forma coinmunis Hagstr. from Sicily, tlto 

 »P. lucenst L. puilosiachijwit TiN.», described by 

 TiNEO, -!-. 



