. Critical researches on the potamogetons. KUNGL. SV. VET. AKADEMIENS HANDLINGAK. BAND 55. N:0 5. 173 Ligulce cito evanescentes. Pedunculus brevis (0,5â1 cm), demum ca. 2 cm longus et deflexus. Spica brevis subglobosa pauciflora. Pistillum stylo subnullo, stigmate parvo rotundato. Fructus parvus, 1,5X1,5 mm rotundatus erostratus 3-carinatus, carina media prominente subgibbosa. This plant of southwestern Australia has been considered to be P. Drummondii. How- ever there must be any misconception, as it very little answers to the description of P. Drummon- dii. It nearly always lacks floating le
. Critical researches on the potamogetons. KUNGL. SV. VET. AKADEMIENS HANDLINGAK. BAND 55. N:0 5. 173 Ligulce cito evanescentes. Pedunculus brevis (0,5â1 cm), demum ca. 2 cm longus et deflexus. Spica brevis subglobosa pauciflora. Pistillum stylo subnullo, stigmate parvo rotundato. Fructus parvus, 1,5X1,5 mm rotundatus erostratus 3-carinatus, carina media prominente subgibbosa. This plant of southwestern Australia has been considered to be P. Drummondii. How- ever there must be any misconception, as it very little answers to the description of P. Drummon- dii. It nearly always lacks floating leaves, has recurved short peduncles, quite beakless fruits etc. The epidermis of the stem lacks a strength- ening layer but possesses a full-numbered circle of rather strong strands. In the bark inside it no bundles appear. The central stele has 0-endodermis and four free bundles separated by strong bast sheaths and arranged as in the foregoing. The style of this species is very slightly developed and the fruit seems to be quite beakless. This fact combined with the above described properties: no floating leaves etc. makes us feel inclined to class this species in a separate group. Principally on account of its stem structure the P. reduncus may be united with the foregoing species. Future researches may possibly alter this arrangement. Distribution. S. Western Australia (hb. Stockholm.). On the label Mr. Ar. Bennett has noted: »not been refound. f. Baron v. Mueller; leg. James Drummond ex Muellers etc. and determined it as P. Drummondii Fig. 90. F. reduncus Hagste. A, Habitas-fignre, â }-. B, Top ot a leaf, â (. C, Pistil, sideview, ',». D, Fruit from the side, {-. E, Transverse section of the stem, showing the central stele, with two larger median bun- dles, each of them having a xylem canal, the interjacent bast cells, and the subepidermal strands, \^. F, Part of the epidermis with an adjoining channel wall and a bast bundle (more enlarg.). P. Clieesemanii Ar
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Keywords: ., bookcentury1900, bookcollectionbiod, bookdecade1910, bookyear1916
