Leaves

Simple leaves (Click here to enlarge simple and compound leaves.)

Compound leaves (with leaflets)

Pinnately compound       

Bipinnately compound

Leaf venation  (Click here to enlarge leaf venation, arrangement, & attachment.)

 Parallel    Pinnate    Palmate

Leaf arrangement  

Alternate      Opposite      Whorled 

Basal rosette    

Leaf attachment

  Sessile   Petiolate 

Perfoliate, auriculate, clasping       

Leaf lobes, sinuses, serrations, teeth
(Click here to enlarge leaf lobes, surfaces, bracts, & hairs.)

Leaf surfaces

Glabrous    Pubescent   

Leaf Modifications

Scales        Needles    

Other leaf terms:

Bracts          

   Phyllaries            

Stem and leaf growth patterns

Appressed: close to or flat against
Ascending: growing upward in a curved fashion
Caespitose: growing in a dense tuft
Declining: curved downward
Decumbent: growing along the ground with an ascending tip
Divergent: spreading
Erect: vertical, not declining or spreading
Ramose: many branched
Recumbent: growing along the ground
Reflexed: sharply declining

Hairs

Hairs are generally called "trichomes" and
hairiness is generally referred to as "pubescence".

 Canescent     

  Strigose    Glandular  

 Tomentose, villose   

   Pilose 

A few terms for hairs:

Canescent (gray/white appearing because of fine hairs)
Ciliate (with marginal hairs)
Hirsute (hairy with course, stiff hairs)
Pilose (long, soft, straight hairs)
Puberulent (minutely pubescent)
Pubescent (hairy)
Pustulose (swellings at the base of hairs)
Sericeous (silky)
Stellate (forked, star-burst-like)
Strigose (pointed, straight, appressed hairs)
Tomentose (densely clothed with woolly hairs)
Trichome (a general term for plant hair)
Villous (clothed with long, soft hairs)

Other Plant, Leaf, and Stem Terms

Herbaceous (herb) and woody
Sub- 
Adnate
Connate
Proximal
Distal
Stipule
Revolute 
Involute
Node
Internode
Caudex
Acaulis

Important reminder

 Just because a plant has one or more of the above words in its name, it does not follow that the plant possess those characteristics.  The person who named the plant may have incorrectly named it, may have had specimens that were not typical, or may have named it relative to other plants, e.g., not all plants named "grandiflora" have large flowers.