172 



J. A. HAGSTROM, CRITICAL RESEARCHES ON THE POTAMOGETONS. 



P. porrigens n. sp. 



Fig. 89. 



Caulis elongatus teres tenuis subfiliformis simplex, internodiis summis elongatis, 

 10—25 cm, a spica primaria ramo internodiis longis prolongatus. Folia natantia 

 parva 15 — 20 X 5 — 6 mm, oblongo-lanceolata, apice obtusa basi attenuata, 5 — 7-nervia, 

 longissime (10 — 15 cm) petiolata, petiolo filiformi; submersa lineari-lanceolata 

 sessilia— subpetiolata, apice obtusa, 50 — 60x3 — 4 — 5 mm, integerrima 3( — 7)-nervia. 

 Ligulce membranacete cito evanescentes breves (5 — 15 mm longa?). Pedunculus sequalis 

 filiformis, 10 — 12 cm longus. Spica 5-verticillata, deflorata 8 — 10 mm longa. Frue- 

 tus non visus. 



This species, the fruetification of which, onaccount 

 of the defective material, can not be described, vet is 

 easy to identify by its elongate filiform upper internodes, 

 peduncles, and petioles and by the minute f loating 

 leaves. Spikes usually with 5 verticils and thus 

 small. The submersed leaves are as to form and size 

 almost quite like those of P. sclerocarpus, but destitute 

 of the midrib canals, there always present, beside which 

 the nervation also is different. To judge from the 

 description of P. Drummondii and from a diagram of 

 the central stele of it drawn by C. Raunki^er in his 

 Anat. Pot. Stud., 265, f. 4, A, P. porrigens would be 

 Fig. B9. p. porrigens haostb. i. Base very closely allied with that species. But the stem-ana- 



i./i and top [h) ..t a Babmersed leaf; the , r r> t~> ■ i~ a. . i - _ *. . / i \ 



rupted linea indicate nervea freqnently tomy of P. DriUUm. nillS : ep. + Sllbep. str. + llg.Stl\ (±) 



+ 0-end. + CC eight-bundlcd, acoord. to Drummond's 

 own spec. (hb. Haun.), and, besides, its habitat is 

 West Australia, in consequence of which I cannot 

 consider them identic. Nor is it congruent to the 

 P. Cheesemanii, with which it shares a common distribution, though extremely nearly 

 related also to that multiform species. 



In the topography of the stem-anatomy we immediately observe the compressed 

 central cylinder with two prominent median bundles (mb) and small lateral ones (Ib), 

 one on either side, all separated by a strong central mechanic tissuc. Besides we 

 notice an O-endodermis, no interlacunar bundles, no strengthening layer, but a ti\\ 

 Bubepidermal strands. Three circles of lacunse of the usual form. 



Distribution. Nova Zelandia: ETokianga, 74, Berggren (hb. Stockholm., 

 Uppsal., Lund.). 



can I" absent, f. B, Floating leaf, j. C, 



i m mat ie crosasec-tion "f the stem show- 



inK the central cylinder, epidermia and aub- 



• pidi i mal stranda : \", mb, median bumlles, //., 



I*, reduncus n. sp. — Fig. 90. 



< 'milis tennis internodiis summis ca. 5 cm longis. Folia Bubmersa membra- 

 naoea lanceolata, apice obtusa basi attenuata sessilia ve] Biibpetiolata 5 7-nervia 

 integerrima ca. 50 — 150x5 — 1<> mm; natantia raiioia ininora longe petiolata obtusa. 



