KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 55- N:0 5- 87 



by a comparison between the fig. 16, H, and 34, C. The epidermis-cells of the leaves 

 are of about cubic form as in the other species. The leaf-apex is certainly fine but 

 not sharp as sometimes is stated, nor acuminate or mucronate as often in the Pusil- 

 loids. The mechanical tissue of the ligules is reduced to the two carinal strands of 

 the other species. Front-field consequently with no strands at all. 



Nethermost at the base of the stem there are a few leaf-less sheaths or scales 

 beautifully coloured in a red-brown tone. A rich ramification distinguishes the species, 

 yet not according to the type way of P. trichoides, but so that the branches of the 

 first rank branch along their whole length with very short internodes, to which may 

 be added that the internodes of the main-shoot are also short, 2 — 4 (upwards 5) cm. 



No hibernating organs of this species ha ve hitherto been described. The rhizomes, 

 creeping on a depth of a few centimeters, might produce hibernating buds but nothing 

 is known of it. But in the stem I have seen such true turios. They consist of 

 transformed short branches in the basal leaf-axils about 15 mm in length. At the 

 base they bear a prophyllum and two scales (Fig. 26, G, 2 and 3). The 4th leaf- 

 organ is an ordinary leaf, but very short and pointed, basally a little grown together 

 with the ligule, the fifth likewise, the other ones following are very short, obtuse, 

 and wholly enclosed in the sheaths. The internodes are somewhat swollen and filled 

 with starch. This way of forming turios we meet with again in P. panormitanus 

 and other Pusilloids. 



Distribution. N. America, Nov. Angl. Tuckerman (hb. Uppsal.), N. Yersey 

 1818, »Herb. Casströmii» (hb. Stockholm.). 



Subsectio 13. Pusilli (Graebner, 1. c. 1907, 106) Hagstr. 



Caulis ± compressus vel rarius subteres pedunculis brevibus. Folia linearia 

 pauci-[3 — 5( — 7)]-nervia basi saepe attenuata apice ± acuta vel cuspidata, suprema 

 interdum ± loculosa vel fere subnatantia obtusa. Ligulce fissse vel integraa, in spatio 

 intercarinali (antico) ut plurimum 8 — 9-nervia (3 — 13). Pistillum brevistylatum stig- 

 mate ± rotundato. Fruetus ± obovatus vel ± rotundatus laevis ± carinatus vel saepius 

 fere ecarinatus. 



The pusillus-grou.]) forms the body of the small-leaved species being represented 

 by species in Europé, Africa, Asia, North and South America; it is absent in Australia 

 and Polynesia except in the Sandwich Islands. 



For want of materials for examination it is unknown to the writer if P. Curtisii 

 Mor. is to be reckoned hereto or not. For the present it is to be looked upon as 

 a »planta dubia». Possibly it may be ranked with the next group or rather, perhaps, 

 with the Hybridi. — Prof. Graebner includes P. Maackianus, P. confervoides and 

 P. trichoides also with the group, but excludes P. limosellifolius and P. Preussii. 



The stem is more or less compressed or flattened as in several preceding groups 

 (usually in the relation 2,5 — 3 : 1), sometimes faintly double-furrowed, more seldom 



