KUNGL. SV. VET. AKADEMIENS HANDHNGAR. BAND 55. N:0 5. 73 



P. acutifolius Link x pusilliis L. (P. suderni aniens n. hybr.). 



Gaulis ± compressus (vide fig. 28, C), statura P. pusilli. Folia parva ut in 

 P. pus., acuta, basi rotundata fere ut in P. acutijolio, nervatura fere intermedia. 

 Pedunclus et spica ut in P. acutif. Hybernacula iis P. pusilli similia. 



At a sudden glance this plant extremely resembles in habit P. jmsillus. The 

 collector has also held it to be so. Beside the habit and the smallness of all parts 

 the turios also resemble those of P. pusillus. Further the lacunar part of the leaves 

 with two large channels on either side of the midrib, at least in the lower half of 

 the leaf, and the central cylinder of the stem are completely as in the species just 

 now mentioned. On the other hand the basis and apex of the leaf have the same 

 form as in P. zosterifolius and P. acutifolius, and the flattened stem, the abundant 

 leaf-schlerenchyma, and the appearance of the ovary point in the same direction. 

 The organs incontestably witnessing the last mentioned to be one of the parents 

 are, above all, the two-whorled, small, head-like spikes, the very short (6 — 8 mm) 

 peduncles, the short leaves and the comparatively long epidermis-cells of the stem 

 (4 — 5 times as long as broad). The peduncle is as to form and anatomy inter- 

 mediate; a single subepidermal bast-bundle is observed. Besides, I refer to the 

 fig. 28, E. 



The nervation of the leaves draws nearer to P. acutijoUus than to pusillus. 

 The marginal strands are very strong. Beside the lateral nerves there is a bast 

 bundle between them and the median lacunar part, and besides, here and there, small, 

 at places interrupted strands in the whole blade and a complete sclerenchyma in 

 the lacunar part also. Numerous spikes are present, all entirely barren. No fertile 

 pollen is found. 



The plant is collected at the most northern border of the distribution area of 

 P. acutifolius and probably belonging to the greatest rarities of the vegetable king- 

 dom. I have named it after my beautiful native county Sudermania, where it has 

 been gathered by Dr. C. J. Hartman. It is labelled »Rorvik prope Hjelmaren, aug. 

 1831. H"* (hb. Uppsal.) and it would be very interesting, if the locality could be 

 found again by botanists living there. 



P. acutifolius Link x zosterifolius Schum. 



P. bambergensis Fischer, Die bayer. Potam. etc. 1907, 98, 21. — P. zosterifo- 

 lius X acutifolius ex Fischer, Beitrage etc. in Mitteil. bayer. bot. Ges. 1904, 377. 



I have seen true specimens of this bastard from several places. Especiallj^ 

 beautiful ones I have received from my friend B. Lagerwall, at Drottningholm. 

 Characters common to all hitherto known forms are the barren spikes, consisting of 

 5—6 verticils, and the short peduncles, 15 — 30, usually 18 — 23 mm. long. Some- 

 times a single nutlet ripens, but this is very rare. The turios are less thick or mas- 



K. Sv. Vet. Ak.id. Handl. Band 55. N;o 5. 10 



