. Carnegie Institution of Washington publication. 34 THF. OPHIOGLOSSALES II. THE EMBRYO. The development of the embryo in the- Ophioglossaceae has been more or less completely studied in Ophioglossum pedunculosum, 0. vulgatum, (). moluccanum, (). pendulum, Botrychium virgintanum, B. lunana, and H. obliquum ( Mettenius I, Bruchmann 1 and 2, Lang 1, Campbell 8, [effrey I, Lyon 1). The first division in the young embryo in all of these is usually approximately transverse, although there may be a good deal of variation in this respect. It is probable that in all cases the primary root, the stem ap
. Carnegie Institution of Washington publication. 34 THF. OPHIOGLOSSALES II. THE EMBRYO. The development of the embryo in the- Ophioglossaceae has been more or less completely studied in Ophioglossum pedunculosum, 0. vulgatum, (). moluccanum, (). pendulum, Botrychium virgintanum, B. lunana, and H. obliquum ( Mettenius I, Bruchmann 1 and 2, Lang 1, Campbell 8, [effrey I, Lyon 1). The first division in the young embryo in all of these is usually approximately transverse, although there may be a good deal of variation in this respect. It is probable that in all cases the primary root, the stem apex, and the foot all arise from the epibasal region. The embryo reaches a very large size before the root emerges from the overlying prothallial tissue and all of the organs of the young sporophyte are very late in developing, so that it is not easy to trace their origin back to the early cell divisions in the young embryo. Much the most conspicuous organ of the young sporophyte is the root, which may reach a very large size and an advanced stage of development before any evidence of the other organs is apparent. Indeed, several roots may be developed before the shoot is established. In Ophioglossum vulgatum and Botrychium lunana, according to Bruchmann's account, the young. Fig. 18.—0pftioglossum moluccanum, \. An old archegonium. X180. B. Two-celled embryo within the archegonium. X180. C. Two sections of an old o. Xi&o. cot,cotyledon; /. h>ot; r,root. sporophyte remains several years under ground before the first green leaf appears above the earth, and it is probable that in Ophioglossum pendulum there is also a long period of underground existence before the first green leaf is developed In Ophioglossum moluccanum, however, and in Botrychium virgintanum, the first leaf developed is a green foliage leaf, which grows rapidly and soon appears above the surface of the ground. "IIIK EMBRYO OK OPHIOGI OSS1 M. The first figures that we have of the embryo of Ophiogloss
Size: 2077px × 1203px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorcarnegie, bookcentury1900, bookdecade1910, bookyear1911
