2.  Internode-section of the stem between two nodes

3. LEAF-two principal parts: blade and the petiole (a leaf without a petiole is sessile).
Simple leaf-consisting of a single blade
Compound leaf-more than one blade, consisting of leaflets or pinnae.
Do you know the difference between a petiole and a rachis?
 4.  Spines: modified leaves designed for defense.  In Acacia, the leafy stipules become the spines.

STEMS
Classified as either herbaceous or woody.
herbaceous stems: typically green and relatively soft, found in annuals
woody stems: hard, found in perennial plants
Remember, in a cactus-the stem is typically flattened and green and the leaves are absent or rudimentary.  Such a stem is called a cladode. Stems are also succulent with considerable water-storing ability.

Tuber: fleshy underground stem with vegetative buds capable of producing a new shoot.
Rhizomes: underground stems that run parallel to the ground and give raise to aerial shoots (asexual reproduction) periodically.
Corms have a lot of stem tissue as compared to a bulb-which is more leafy in nature.
 
 
 

POLLINATION
 Many plants are wind pollinated including the conifers, grasses, birches, alders, and oaks.  They produce copious amounts of pollen.  The stigmas of wind-pollinated plants are commonly large and feathery to enhance pollen-trapping ability.
Insects are the most important pollinators of angiosperm flowers.  They visit the flower for the nectar and pollen rewards, but incidentally perform the function of transferring the immature male gametophyte to the stigma.  Insects locate flowers by odor primarily but are also guided by color and overall shape.  Bees preferentially visit yellow or blue flowers, whereas moths, which emerge in the evening, are attracted to white or cream flowers, which are more discernible at that time. In contrast, the flowers of wind-pollinated plants are typically minute, green, or brown, often with no petals and lacking nectar.