KTJNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 55- NIO 5. 223 



Already S. Almquist, having first established this hybrid (see the Index !), has 

 divided the forms in two groups, one in habit and vegetative conditions very like 

 P. gramineus, the other more similar to P. perjoliatus (in Hartman, Handb. ed. 12, 

 1889, 49). The former group C. Raunkl^r låter on has named subgr aminens, the 

 latter subperfoliatus (Danske Blomsterpl. 1896, 100). As the forms or crosses, however, 

 are so innumerable as here is the case, it has proved necessary and practically 

 suitable partly to establish an intermediate group, partly to limit the group-characters 

 to one or a couple of more prominent characters, or to the properties of a certain 

 part of each plant. The upper portion of stem with its involucral leaves and different 

 habit presents itself as most convenient and most easily obtainable (O. Hagström, 1. c). 



a SUbgramineus (Raunkler) Hagstr. : — Folia floralia primaria basi angustata 

 ± petiolata, secundaria semper conspicue ssepe longe petiolata subcoriacea— eoriacea. — 

 Fig. 106. A. — 



p subperfoliatus (Raunki^er) Hagstr.: — Folia floralia primaria basi cordata 

 sessilia, secundaria basi cordata — rotundata sessilia. — Fig. 107. A. — 



Y subintermedius n. nom. 7 intermedius Hagstr., 1. c. 1 — Folia floralia pri- 

 maria ambo, aut saltem superius, basi lanceolata (inferius interdum basi rotundatum) 

 quam plurimum sessilia, secundaria basi lanceolata sessilia — breve petiolata membra- 

 nacea aut interdum subcoriacea. — Fig. 108. A. — 



Folia floralia primaria and secundaria imply the first and the second pair of 

 opposite involucral or floral leaves appearing in the spike region. In the exceptional 

 cases, when merely a single leaf appears at the primary spike \ve proceed to the 

 spike next above, belonging to a first rank branch. 



In distinguishing the different forms within the particular series, there is no 

 more convenient principle of division than the size and form of the submersed leaves. 

 The spikes and the flowers are in most cases deformed, consequently not employable. 

 Nor are the anatomical facts available on account of their being inconstant. By this 

 method the mensural conditions of the leaves certainly seem to get more importance 

 than usual, but that cannot be avoided, if 3^011 wish to arrive at any clearness as to 

 all those innumerable crosses. 



Synopsis of forms: 



* subgramineus (Raunki^r) Hagstr. 



f. innominatus (Tis.) P. nitens e. innominatus Tis., 1. c. n:o 49: — Folia cau- 

 lina submersa ovali-lanceolata basi ± rotundata, 70—75x12—15 mm; ligulce ± persi- 

 stentes; spicce demum floribus apertis remotis. 



f. involutus Fryer in The Journ. Bot., 1896, 1, t. 353, 354. — Folia caulina 

 subm. ovali-lanceolata basi rotundata vel ± subcordata, 80 — 85 x 15 — 18 mm; ligulce 

 tenues caducse ; spicx parvse floribus ± abortivis. 



1 The naine of intermedius, as earlier used by Tiselius of a »var. S» of P. nitens (Pot. suec. exs. fasc. 

 I 11:0 48), must be changed for another. 



