Oaks

Oaks are in the division Anthophyta, family Fagaceae, genus Quercus.  They are characterized by pendulous catkins, and acorns as fruits.  Oaks in California typically occupy drier habitats.

Oats

Oblique

Oblique is an angle that is less than 90 degrees or greater than 90 degrees but NOT 90 degrees.  In plant cells it describes the angle of the cross walls of the vascular cells in the vascular bundle.  

Obtuse

                    DIAGRAM:  Leaf Apex

                          PHOTO:  

Olive

Omnivores

Oogonia

                            DIAGRAM:  

                          PHOTO:  Fucus Oogonium / Fucus Oogonium
                                           Saprolgenia Oogonium / Saprolegnia Oogonium

Oomycophyta

Oospores

Open Nutrient Cycles

Operculum

                   DIAGRAM:  

                          PHOTO:  Moss Capsule Cross Section

Ophioglossales

                 DIAGRAM:  Pterophyta/Ophioglossales

                       PHOTO:  

Opposite Charges

Opposite Leaves

Opposite refers to the arrangement of either buds or leaves along the stem. Opposite budding or leaves is two buds or leaves per node.

                    DIAGRAM:  Opposite Leaves

                          PHOTO:  

Orange

Orchidaceae

Orchids

Order

Organelles

Organic

(substances)

Organic Matter

(in soil)

Organic Fertilizers

Organogenesis

Oriental Lotus

Ornamentals

Oscillatoria

                    DIAGRAM:  Oscillatoria

                          PHOTO:  Oscillatoria / Oscillatoria

Osmosis

Ostiole

                   DIAGRAM:  

                          PHOTO:  Fucus / Fucus

Osmotic potential

Other-compatible

Otto Drunfels

Outer Integument

Ovary Wall

Ovary

                    DIAGRAM:  Ovary Position

                          PHOTO:  Cross Section of Ovary / Cross Section of Ovary
                                           Narcissus / Narcissus / Narcissus / Narcissus / Narcissus
                                           Composite Flower / Composite Flower

Ovules 

                  DIAGRAM:  

                          PHOTO:  Cross Section of Ovary / Cross Section of Ovary
                                           Narcissus / Narcissus / Narcissus

Overgrazing

Overlapping Scales

(cones)

Ovules

Oxygen

Oxygenation

(of water)