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



95 



str 



m 



str 



n 1 



B 





axils next below the primary spike spike-bearing branches are often met with or the 

 young branches occurring there are transformed into turios, vvhich appear partly as 

 wholly transformed short branches, partly as branches with meta- 

 morphosed tops. A 



The stem is compressed in the relation of 3 : 1 with rounded 

 margins. Its anatomy corresponds nearty with that of P. foliosus. vb 

 Central stele terete and consisting of a compound bundle (circular 

 diagram), subepidermal strands as the type, no pseudo-hypoderma 

 and no interlacunar strands. Epidermis-cells of the upper part 

 of an internode 2—5 times as long as broad, in the lower portion 

 more stretched. — The peduncle, flattened like the stem and 

 20 — 65 mm in length, lacks seldom, if ever, a few subepidermal 

 strands. The typical pseudo-hypoderma is present and the bun- 

 dles, 4(— 6 a 7) in number, run separately as is shown in the fig. 

 37, A (XX, accidentally occurring bundles). 



The leaf presents a row of large-celled channels on either side 

 of the midrib, lacunulse, and usually four strands of bast-bundles. 

 The regular occurrence of an exteriör side nerve and its course 

 are already known from old times and correctly figured by Cha- 

 misso and Schlechtendal in Linnaea, 1827, t. IV, f. 5. In the 

 same work is also pointed out the »rete cellularum» of the upper 

 leaves »quod totum occupat interstitium nervum inter primarium i 

 et laterales». The involucral leaves of this species, namely, are 

 often transformed into a sort of primitive floating leaves by a 

 metamorphosis of the upper half or third part in such a manner 

 as is described under P. ruiilus. »Rete cellularum» is not a cellulär 

 tissue but the small air cells or lacunulse of the leaves. But no r 



stomata can be observed in this species either. Front-field of e Flg - 3 , 7 - _ p - muc >'° nat " s 



1 öchr. A, Transverse sec- 



the ligules 11 — 13-fibrOUS. tio » of the peduncle show- 



_ . ing the situation of the 



Ihe stem-leaves or this species are usually not much bnndies, str, bast strands, 

 stretched, commonly 50 — 75 mm, but in a variety from Sweden, r f ' ste VieTf SV b"™ 60 the 

 Gestricia (see below) I have found a leaf-length of as much as 100 m }^ le > t mid J ei " P° ltio " 



v ' c with 4 strands of subepid. 



mm (f. borealis: folia caulina longissima). scierenchyma (str),xsigni- 



The upper part of the style is protracted backwards (out- strands nearer to the leaf- 



ward) into a little beak. The fruit has about the same shape as J 36 »™ utorli^nerres**?'. 



in P. panormitanus, but is a little larger, 2,2—2,5 mm x 1.5 mm, £• m Pistil i. si ^ e "J ie Y' j- 



1 ° ' D, Top of a leaf, showing 



and with a more obvious keel. However, it varies with conspi- the nervation and form of 



tli 6 «ip6x -f-« E TmnsvGrsG 



cuous bosses on the lid, especially at the base, by which it chances seetion of å ugnie in young 

 to coincide more with the pusHlus-irmt. ££; ¥ ' r > ridge ' ic ' {ront ' 



Besides it varies with narrower or broader leaves (ff. angusti- 

 folius Fisch. et latifolius Ruthe ap. Fischer) and with more obtuse apex (f. obtusior 

 Fisch.). A small-leaved form is f. minor Tis., Pot suec. exs. f. III, no. 101, 1897. 



