. Critical researches on the potamogetons. 38 J. O. HAGSTROM, CRITICAL RESEARCHES ON THE POTAMOGETONS. end str sed validse, persistentes semper fissse badeo-virides, ut ligulae marginibus albidis niti- dis. Pedunciihis brevis, 25—35 mm longus. Spica 20 mm longa, 4—5-verticillata, interstitiis brevibus. Stylus brevis stigmate ovali, postice in rostellum in fructu ma- ture ssepe persistens protracto. Fructus maturus oblique obovatus 3 mm longus 2 mm latus, siccus subcarinatus in vivo verisimiliter dorso rotundatus, rostro brevi apicali v. subapicali. — Fig. 13. Anatomy of the stem and leaves: Th
. Critical researches on the potamogetons. 38 J. O. HAGSTROM, CRITICAL RESEARCHES ON THE POTAMOGETONS. end str sed validse, persistentes semper fissse badeo-virides, ut ligulae marginibus albidis niti- dis. Pedunciihis brevis, 25—35 mm longus. Spica 20 mm longa, 4—5-verticillata, interstitiis brevibus. Stylus brevis stigmate ovali, postice in rostellum in fructu ma- ture ssepe persistens protracto. Fructus maturus oblique obovatus 3 mm longus 2 mm latus, siccus subcarinatus in vivo verisimiliter dorso rotundatus, rostro brevi apicali v. subapicali. — Fig. 13. Anatomy of the stem and leaves: The central cylinder and endodermis of the stem chiefly as in the precedent species, yet the lateral bundles are often reduced so that the original three bundles fuse into one single bundle by which the stele becomes four-bundled. The epi- dermis consists of very long and narrow cells, about ten times as long as the width. Inside it is co- vered with a single stratum of cells wherein occasionally occur faint- er bast-bundles, peculiar to this species, though a tendency hereto is observed also in P. vaginatus. In the lacunar part, besides, there is a circle of about 10—15 strands, or fewer in very thin stems, some- times an indication of a second circle. The epidermis of the leaf consists of small cubic cells just as in all the other species of the subgenus. The arrangement of the lacunar system does not dif- fer essentially from that of P. vaginatus as a comparison of the two figures (12 ^ and 13 D) will show. Three vascular bundles occur, a median one forming the midrib and two lateral ones nearer to the borders separated from the marginal epidermis by 4—5 cell-strata, in the broader leaves. In the very border towards the upper surface either immediately up to the epidermis or separated from it by a single cell-layer there appears a very strong bastcell-bundle, and subepidemally in the upper surface 2—3 and in the lower surface 3—4 strong bast-bnndles. It is this p
Size: 1686px × 1482px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionbiod, bookdecade1910, bookyear1916
