Glands on the leaf, petiole and stipule.

 

Many plants have glands or gland-like structures in various positions on the leaves, petioles or stipules. On the leaf blade they may be visible on the upper or lower surface, or both. In some cases they are called extra-floral nectaries.  Use a hand lens or microscope to look for the glands as they are not always easy to see. Sometimes it is difficult to distinguish glands and gland-like structures from marks made by insect or fungal damage, especially in dried material where colour, texture and shape may be lost.

 

Neotropical Euphorbiaceae and related families (Peraceae, Phyllanthaceae, Picrodendraceae, Putranjivaceae). In this group the glands/gland-like structures are often distributed at or near the base of the leaf blade (i.e. in about the lower 1/5th of the leaf), more or less bordering the leaf margin, or on the leaf teeth, or in some combination of these three patterns. Less often they are distributed more centrally along the length of the leaf, or (rarely) are scattered sparsely to densely over the entire leaf blade. Glands/gland-like structures occur in a variety of shapes and sizes, some less than 1 mm across.  In the interactive Key the presence of glandular hairs is treated as a separate feature (under  indumentum type).  Sometimes  peltate hairs (disc-like hairs) can be misinterpreted as small glands. In the Key we are aware of a number of errors in data interpretation and scoring, and are working to correct these as soon as possible. 

 

Examples from neotropical taxa.

 

 

 

 

Aleurites moluccana glands on leaf base.JPG           Aparisthmium cordatum glands at leaf base 2.JPG           Tetrochidium glands at leaf base 3.JPG

 

á Aleurites  (glands at leaf base)                                 á  Aparisthmium (glands at leaf base)                      á Tetrochidium  (glands at petiole apex)

 

 

 

 Ricinus communis peltate leaf base and glands.JPG           Discocaprus essequeboensis glands at leaf base.JPG            Brasiliocroton mamoninha glands 3.JPG

 

  á  Ricinus (glands at petiole apex)                            á Discocarpus (glands at petiole apex)             á Brasiliocroton (glands at petiole apex) 

 

 

 

 Croton glands at leaf base 3 and steallate hairs.JPG         Alchornea incurvata 5203 fem glands2.jpg           Conceveiba guianensis glands at leaf base 4.JPG

 

    á  Croton (glands at petiole apex)                   á Alchornea (glands at petiole apex)                á Concevebia (glands near leaf base)

 

                                

 

  Alchorneopsis floribunda glands at leaf base.JPG       Bernardia polymorpha leaf glands and fruit.JPG       Bernardia polymorpha glands on leaf 4.JPG

 

     á Alchorneopsis (glands near leaf base)             á  Bernardia (glands near leaf base)                       á Bermardia

 

 

Maprounea glands at leaf base 1.JPG        Didymocistus chrysadenius glands on lower leaf surface 2.JPG     Romanoa tamnoides glands on leaf surface.JPG

 

 

 á Maprounea                                                 á Didymocistus (lower surface of leaf,          á Romanoa                                          

peltate hairs orange, glands red)                                                                     

 

 

 

Ditta glands on leaf margin.JPG             Colliguaja glands on leaf margin.JPG             Gymnanthes Glands.JPG

 

 

á  Ditta (glands at leaf margin)                           á Colliguaja (glands at leaf margin)             á Gymnanthes                               

 

 

Vaupesia glands at leaf base 1.JPG

 

á Vaupesia (glands at petiole apex)