摘要:

The primary trimerous pattern of the flower ofEchinodorus amazonicusRataj is clearly exhibited in the earliest developmental stages. After the inception of three sepals, theree alternisepalous petal‐stamen complexes arise, each of which, at successively higher levels of the primordia, consists of a petal, a pair of stamens, and a single stamen. In alternation with these three petal‐stamen complexes three groups of three pistil (carpel) primordia are formed. Subsequent pistil primordia are formed rapidly in alternation with the preceding ones. Teratological buds were observed in which one pistil primordium appeared to be replaced by a normal stamen primordium. General features of the flowers of the Alismatales are summarized in developmental fashion which includes the mature flower as a final stage. With the exception ofLimnocharisand probablyWisneria, all alismatalean flowers appear to be characterized by antipetalous stamen (or staminodial) paris. In members studied thus far, the basic trimery differs radically from that found in certain taxa of the Magnolii

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1978.tb01396.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

A description of the developmental anatomy of the flower of a self‐incompatible member of the family Commelinaceae,Gibasis vnustula(Kunth) D. R. Hunst, is presented. Particular attention has been paid to the anther (with its wall of the reduced‐type, recorded for the first time in the Commelinaceac), the stigma, the hollow style, embryo‐sac and the development of the vasculature. The occurrence of axile as opposed to parietal placentation is also discussed. An attempt to relate development events in the sex organs has been made.The study is both histological and histochemical. Enhanced protein and RNA contents have been found in the tapetum and sporogenous tissue at the time that the tapetum becomes periplasmodial, and in both the stigma papillae cells and stigmatoid cells at maturity. The secretion found in the embryo‐sac also stain heavily for total protein

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1978.tb01397.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

By comparison with the major modern plant communities of southern Patagonia, the changing post‐glacial vegetation of the region is reconstructed from macrofossils derived from deposits in the Cueva del Mylodon, Ultima Esperanza, S. Chile. The oldest deposits, carbon‐dated asc.12,400 B.P., comprise dung of the extinct ground slothMylodon darwiniiand show the animal to have fed entirely on Cyperaceae, Gramineae and species associated with these in the modern cool, wet sedge‐grasslands of western Patagonia, communities which would be expected after the retreat of the ice. Overlying deposits of well‐preserved, wind‐blown leaf‐litter permitted some quantitative analyses which show a rise of evergreen forest dominated byNothofagus betuloidesthat reached its maximumc.7000 B.P. and then declined as it was replaced by deciduousN. pumilioforest. A break in the fossil plant record, covering the human occupation about 5643 B.P. and the subsequent final appearance ofMylodonremains, is followed by evidence of mixed evergreen/deciduous forest in whichNothofagus pumiliogradually increases in importance to give deciduous forest some 2500 years ago similar to that found in the environs of the cave in historical times. Comparison with pollen diagrams shows that the modern climatic and vegetation difference between E. Fudgia and Ultima Eeperanza has persisted throughout the post‐g

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1978.tb01398.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

SilenesectionElisantheis a well‐defined group containing (in Europe) the following species:S. alba, S. diclinis, S. dioica, S. heuffeliiandS. marizii(dioecious perennials or biennials) andS. noctifloara(a self‐compatible hermaphrodite annual). Crosses were attempted among these species, and between these species and members of otherSilenesections.Crosses among the first five species revealed partial cross‐incompatibility with moderate hybrid fertility. S.albaproved especially incompatible withS. diclinis. S. noctiflorawould not cross at all with other members of the section. It is suggested thatS. noctifloraevolved from a dioecious precursor of S.alba, the species to which it is most similar in morphology, distribution and habitat; hybrid sterility, even without incompatibility, would have assured mutual isolation.Crosses with species from other sections ofSilenehave usually either failed consistently or revealed high cross‐incompatibility with hybrid sterility. Those crosses which were successful have all been within the boundaries of the old genusMelandrium, or withLychnis

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1978.tb01399.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

The longstanding problem of the true identity of the juvenile conifer clone usually known asChamaecyparis obtusa‘Sanderi’ has been solved by comparing gas chromatograms of solvent extracts of foliage specimens. Forty‐seven species of the northern Cupressaceae were compared with ‘Sanderi’ but close similarity was shown only by juvenile forms ofThuja orientalis.All other species studied showed significant, usually major, di

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1978.tb01400.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1978.tb01396a.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY