*MYRTACEAE Family *

                      *MYRTACEAE *

Distribution:-

                          The family comprises 114 genera and about 3000 species widely distributed in tropical regions of the world. In India, 14 genera and about 165 species are found. Common examples are Callistemon, Eugenia, Eucalyptus, Psidium, Syzygium etc. Eugenia(600 species), Eucalyptus (500 species) and Syzygium (300 species) are some large genera of the family.

 Salient feature: -

                                Plants are mostly trees or shrubs with aromatic fragrance.

 Leaves: -

                  Leaves are simple, entire, exstipulate, shortly petiolate, mostly opposite (Psidium), rarely alternate (Eucaplyptus) and with oil glands.

 

Description:-

                        Flowers are insect pollinated. The insects are attracted by nectar – secreting disc around the ovary. Seeds are dispersed by winds, birds or animals. In Callistemon, flowers are pollinated by birds.

 Inflorescence: -

                             May be raceme (Barringtonia), spike (Callistemon), cymose, panicle or rarely flowers may be solitary (Myrtus and Psidium). 

Flowers: -

                   Bracteate, complete, hermaphrodite, actinomorphic and usually epigynous (Myrtus and Psidium), rarely perigynous.

 Calyx: -

                Consists of 4 or 5 sepals, connate at the base and united with receptacle cup to form hypanthium, lobes free and quincuncial, rarely valvate. In Eucalyptus, sepals are minute or absent. 

Corolla: -

                 Consists of 4-5 petals, usually free, imbricate often quincuncial or connate to form operculum (Eucalyptus). Petals in Eucalyptus fall off quickly to expose stamens. 

  

Androecium: -

                          Consists of indefinite number of stamens, all free or slightly connate at the base, arranged in several whorls, sometimes in bundle opposite the petals. Anthers are usually versatile or dorsally fixed, dithecous, introrse and dehiscing by longitudinal slits or sometimes apically. In Callistemon, the filaments are scarlet red and form a brush like structure. Stamens in Melaleuca are polyadelphous and in one whorl and bundles are equal to the number of petals. 

Gynoecium: -

                         Consists of 2-5 or several carpels, united to form an inferior or semi inferior, 2-5 locular ovary (number equal to the number of carpels) with 2 to many obliquely pendulous, campylo- or anatropous ovules in each chamber in axile, rarely parietal placentation. Style is one and stigma is simple.

Fruit:-

             Loculicidal or septicidal dehiscent capsule but may be drupe, nut or berry (Psidium). Seeds are angular, cylindric, or compressed and non – endospermic or with scanty endosperm.

 Floral formula: -

                             Br K(4-5) C4-5 A∞ G (2-5)or∞

 Floral diagra:-

                  Callistemon lanceolatus

 Economic Importance

•  1. The family includes many economically important plants. Many species produce edible fruits e.g. Psidium guajava L. (guava), P. cattleianum Sabine (strawberry guava), Eugenia uniflora (Surinam cherry), Syzygium cumini , S. jambos (rose apple), S. aromaticum (the clove used as spice) etc.
•  2. Valuable timber is obtained from many species of Eucalyptus (E. cerebra, E. paniculata, E. punctata, E. leucoxylon ) and Syzygium cumini. 
• 3. Some plants are medicinally important, e,gSyzygium cumini (seeds useful in diarrhea, dysentery and diabetes), Melaleuca leucadendron (cajaput tree) (yield cajaput oil used in laryngitis and bronchitis), Eucalyptus leucoxylon, E. elaeophora, E. globules (medicinally important eucalyptus oil extracted from leaves) etc. Clove oil extracted from cloves of Syzygium aromaticumis used in toothaches and oil baby rum.
• 4. Several plants are grown for their ornamental value, e.g. Callistemon (bottle brush) (C. lanceolatus, C. viminalis, C. linearis etc.), Eucalyptus (species grown for timber value), Myrtus communis etc.