evolution of sorus in pteridophytes?
480788
Another way you can look at sorus evolution is to consider the sporangia. The more primitive ferns are called eusporangiate ferns and their sori are made up of a clump of simple sporangia that release their spores by opening up a pore or slit (see first pic). The more advanced ferns are called leptosporangiate ferns and their sori are made up of a clump of smaller sporangia that have a specialized line of cells called an annulus and open when the annulus dries and rips the sporangium open to release spores explosively. As one of the other answers notes, there is a further development of these sori from being superficial (on the surface of the frond), to being protected by a simple indusium formed by a recurved frond margin, to a more sophisticated indusium.
1038523
Several types. Read about it at http://horticulture.coafes.umn.edu/vd/h5015/99papers/kostreba.htm
425795
No. \nGeophytes are those plants that have their growing buds below the ground. They usually have parts modified as storage organs (roots and stems forming bulbs, rhyzomes, etc) and are able to undergo unfavorable periods by staying within the soil, with their buds well protected. Thus, they're perennial.\nOn the contrary, terophytes are annual plants. These are usually grasses and forbs, plants that quickly grow, produce flowers and many seeds, and then die with the onset of unfavorable conditions. They don´t have storage organs, because they do not rely on resistance, but rather on producing many offspring that will grow in the next favorable season.
834077
phloxes -  a kind of plant
1150426
Plant tissue cultures isolated from even a single cell can show variation after repeated subculture. Distinct lines can be selected with their own particular morphology and physiology. It suggests that the tissue culture contains a population of genotypes whose proportion can be altered by imposing an appropriate selection pressure. This variation can be transmitted to plants regenerated from the tissue cultures, and is called somaclonal variation. It provides an additional source of novel variation for exploitation by plant breeders.
406714
plants and roots of plants
646025
Yes.\n\nSpartina anglica is a species which reproduces sexually and naturally mutated late in the 19th century from a parent species which only reproduces vegetably. Originally it was an accidental hybrid between S. maritima and the closely related S. alterniflora and incapable of producing seeds, but capable of spreading by vegetative means. A mutation allowed S. anglica to begin producing viable seeds, but it does not hybridize with either S. maritima or S. alterniflora due to chromasome doubling. This species normally out-competes other cord grasses, so it would be difficult to maintain the position that this is some sort of "slow decline in species" as it is a prime example of survival of the fittest and there is some concern it will lead to the extinction of some of the species that were it's ancestors.
1071155
When was this person an active botanist? I know a few Filipino botanists and know of many from the past ... but I have not heard of an Escudero ...
1181775
http://plants.usda.gov/index.html
834603
what kind of plant is it ? some do.
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http://www.olympusconfocal.com/gallery/plants/index.html\n\nIf this doesn't work try Google images.
615648
both are different species belonging to same genus
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stamen=male and pistil=female
203528
go to google.com or look under  plants.com
317556
Flower\nIf both sexes are in the same flower (and plant) then it is a HERMAPHRODITE\nIf not, then they will be female and male plants (of the same species)
1128758
"The oldest indications for the existence of real land plants have been found in cores from boreholes in Oman. They contained fours of mutually connected spores (tetrads) enveloped by remains of the spore sac in which they had been formed. Research on the spore walls point to a relationship with the liverworts. The fossils have been found in the Middle Ordovician and are about 475 million years old."\n\nSee the link below for 2 pages of info on the development of this.
665052
Plants, i think. look in a dictionnary or online.