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



183 



styles and small stigmas. The top of the submersed leaves gradually 

 tapered into a blunt 5-nerved apex. As to shape and nervation 

 these leaves remind much of P. capensis. The very habitus also and 

 the stem-anatomy, the styles etc. bear resemblance to the same 

 species. The pollen of the specimen examined lack well-shaped and fer- 

 tile grains, which makes me think that the plant may be a hybrid. 

 This view is supported by the peculiarity in the stem-anatomy that 

 the endodermis of the lower internodes consists of O-cells, vvhereas it 

 higher up has typical £7-cells. In the latter case the diagram shows 

 nearly complete correspondence with P. capensis. 



Anatomy: The epidermis has usually, at least locally, a one- 

 celled hypoderma, in which at intervals bast-bundles appear. Inter- 

 lacunarly there are generally two circles of bast- and vascular bundles. 

 The central cylinder, basally in the stem exhibiting 8 free bundles, 

 gets the number a little reduced at the middle of it by fusion of part 

 of the låter al bundles. 



Provided that P. promontoricus is a capensis-hybrld the other a 

 parent species should be looked for among the Amplifolii (P. 

 fibrosusl). 



Distribution. South Africa: »Promont. Bona? Spei. Drege» (hb. 

 Uppsal.). a 



Subsectio 21. Nodosi Hagstr. 



Caulis ut in praecedente. Folia natantia longe petiolata; sub- 

 mersa petiolata, media in parte et secundum nervös prsesertim prin- 

 cipales valde lacunosa, serrulata. Pistillum et fruetus ut in Amplijoliis. 

 Anatomia caulis: O-endodermis, fasciculi libriformes corticales typice 

 desunt. 



In most of its properties corresponding with the Amplifolius-group 

 and occupying by its one-celled leaf-teeth an intermediate position 

 between the group just mentioned and the Lucentes, P. nodosus is to 

 be classed as a group by itself. The denticulation of this species is 

 more fugacious than that of the others and seems to be of slight 

 significance in the life of the plant. Perhaps it might be regarded 

 as an ancestral feature. 



C 



Fig. 94. P. pro- 

 montorieus Hagstk. 



A, Stem-leaf, the 8th 

 from the top down- 

 ward, a, basal portion, 

 b, upper half, J . />', 

 Top of a leaf a little 

 higher up (sonuwliul 

 enlarged). C, Pist ils, 



Apild LAMARCK, EllQ. mét. bot. SUppl. IV, 1816, 535. HaGSTRÖM "• side-vie^, h ven- 



trål yiew, |. 



ex Baagöe, Vidensk. Medd. Nat. För. Kjöbh. 1903, 179. - - P. indicus 



Roxb., Fl. Ind. I, 1820, 469? P. petiolaris Presl, Delicise prag., I, 1822, 151. — 



P. nodosiis Poiret. 



