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In this article we will discuss about the classification of Rosidae:- 1. Lytheraceae 2. Combretaceae.
Family # 1. Lytheraceae:
Salient Features of Lytheraceae:
The family includes 500-600 species, generally herbs, some shrubs or trees. It includes 32 genera.
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The family is cosmopolitan in distribution mostly distributed in tropics. The family named so after the genus Lythrum (Loosestrifes), Lythrum salicaria (Purple loosestrife). It also includes Lawsonia inermis (Henna) a woody shrub. It now includes the pomegranate, formerly Classed in a separate family Punicaceae. The family also includes widely cultivated crape myrtle tree. Hydrolythrum wallichi is an aquatic plant.
Vegetative Characters of Lytheraceae:
Plants are generally herbs or shrubs or small trees. Plants non-succulant, helophytic to xerophytic or hydrophytic (Rotala, Ammania).
Leaves:
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Simple, usually opposite, rarely alternate or whorled; petiolate or sessile, gland dotted or not, exstipulate or minutely stipulate, lamina entire, pinnately veined.
Floral Characters of Lytheraceae:
Inflorescence:
Solitary or cymose, panicle, raceme or verticils. Usually cymose, terminal or axillary.
Flower:
Actinomorphic, bisexual, perigynous paired bracteolate, tetra- hexamerous, zygomorphic flower is Cuphea, in Lofoensia the flower is 8-16 merous. While Peplis and Ammannia sp is apetalous.
Calyx:
4-8-16 rarely absent, free or fused (cupule), floral tube extends beyond level of insertion of corolla. Tubular, companulate, urceolate (rare), persistent, valvate. Epicalyx usually present, rarely absent.
Corolla:
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4-8-16 polypetalous, at the mouth of hypanthium, plicate, unequal but not bilabiate or regular, red, purple, orange, petals clawed or sessile. Crumpled in the bud. Absent in Peplis.
Androecium:
Usually double the number of petals to many, when numerous maturing centripetally, adnate to the hypanthium, all equal or rarely unequal, polyandrous, all fertile stamen, polystemonous, alternisepalous or oppositisepalous, inflexed in bud or erect, in Lagerstroemia stamen in two whorls, outer whorl alternate to petals inserted on the inside of receptacle cup or hypanthium, anthers dithecous, introrse. Rotala has only one stamen.
Gynoecium:
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2-6 carpels, syncarpous, superior or semiinferior, axile placentation, ovules anatropus, rarely parietal placentation,. Style-1 with capitate stigma.
Fruit:
Capsule or fleshy.
Seed:
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Non endospermic winged (Lagerstroemia) or wingless, 2 cotyledons, folded in Lagerstroemia. Embryo straight, achlorophyllous.
Economic Importance of Lytheraceae:
1. Lawsonia innermis:
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Leaves produce dye called henna or Mehndi. It is used to colour or dye hair, hands or palms etc. It is a hedge plant.
2. Woodfordia fruiticosa:
Also produces dye for tanning and dyeing silk, the wood and flowers are also used in Ha wan samagri.
3. Lagerstroemia sp.:
Many species are ornamental grown for beautiful flowers.
4. Cuphea lanceolata:
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Red flowered Pot plant or garden ornamental annual plant.
5. Lythrum salicaria:
Ornamental pot plant.
6. Cuphea ignea:
Cigar flower – ornamental.
Systematics:
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Lytheraceae is related to Myrtaceae, Melastromaceae and Onagraceae. Punica was also included into it. But it has been separted to Punicaceae.
Classification:
According to APG II System:
Kingdom: Plantae
Unranked: Angiospermae
Unranked: Eudicots
Order: Myrtales.
According to APG III System:
Unranked: Core angiosperms
Unranked: Core eudicots
Super order: Rosanae
Order: Myrtales
The family Lytheraceae is divided into five subfamilies:
1. Subfamily: Lythroideae
Family Lytheraceae with 28 genera.
2. Subfamily: Punicoideae
Punicaceae — Punica
3. Subfamily: Sonneratioideae
Sonneratiaceae —Sonneratia
4. Subfamily: Duabangoideae
Duabangaceae — Duabanga
5. Subfamily: Trapoideae
Trapaceae — Trapa.
Family # 2. Combretaceae:
Salient Features of Combretaceae:
The family Combretaceae includes. 20 genera and 600 species of trees, shrubs and lianas. It includes the Leadwood tree (Combretum inbrebe). Mangrove plants are Conocarpus, Laguncularia and Lumnitzera. It is widespread in tropics and subtropics of the world. Some members produce useful construction timber e.g. idigbo from Terminalia ivorensis.
Vegetative Characters of Combretaceae:
Generally, trees (Terminalia), woody lianas (Quisqualis, Combretum). Lumnitzera littoria is mangrove plant. Generally plants when climbing are stem twiners or scrambling (hooks or petiole bases).
In Combretum twining is anticlockwise.
Leaves:
Alternate, opposite, (Quisqualis) or whorled, exstipulate, petiolate, simple, entire, unicostate reticulate.
Floral Characters of Combretaceae:
Inflorescence:
Raceme, panicle, spike (Quisqualis), Head (Anogeissus).
Flower:
Usually small, actinormorphic, Braceate, pedicellate or sessile, very rarely zygomorphic, bisexual 5-8 merous, epigynous, tubular free hypanthium present, adnate tubular base of calyx forms hypanthium.
Calyx:
4-8, gamosepalous, fuse to form calyx tube valvate rarely imbricate.
Corolla:
Equal to the number of sepals, polypetalous, tubular, absent in Terminalia, valvate, twisted (Quisqualis) or imbricate.
Androecium:
5-10 in two whorls or many. Sometimes the outer whorl is missing all filaments equal in size and free from perianth, rarely coherent or grouped. All stamens fertile, Anthers dorsifixed or vesrsatile, dithecous.
Gynoecium:
2-5 carpels, syncarpous, inferior, unilocular angular or ribbed of calyx lobes, pendulous placentation, style present, absent in Terminalia. Stigma capitate or pointed, epigynouns nectar disk is present.
Fruit:
Leathery, one seeded drupe winged (Samaroid) or not, or capsule or samara. Drupe with separable pyrenes in Terminalia or with one stone.
Seed:
Non-endospermic, Cotyledonous spirally twisted or rolled or folded.
Economic Importance of Combretaceae:
A. Ornamental:
1. Bucida buceras (Black olive tree)
2. Quisqualis indica (Rangoon creeper)
3. Combretum sp.
4. Terminalia arjun (Aijun) Avenue tree.
5. Terminalia catalpa (Jangali badam).
B. Medicinal:
1. Terminalia arjuna — (Arjun) Bark is a caridiac tonic.
2. Terminalia bellarica — (Bahera) Both are of great medical property and with Amla together form triphala.
3. Terminalia chebula — (Harr)
4. Calycopteris floribunds — For dysentery and Malaria.
5. Combretum acuminatum —Leaves anthelmintic.
C. Timber:
Wood used as timber, for making agricultural tools and cabinets etc.
1. Anogeissus acuminata
2. A. latifolia
3. Terminalia alata
4. T. catalpa.
5. T. ivorensis (Indigo timber)
6. T. paniculata
7. T. tomentosa
D. Tanning and Dyeing:
Terminalia alata
T. catalpa
T. chebula
T. ivorensis
ADVERTISEMENTS:
Bark and fruits used for tanning and dyeing as they are rich source of tannius.
E. Edible:
1. Nuts of many Terminalia such as T. catalpa (Indian almond) are edible.
F. Gum:
Commerical gum is obtained from species of Terminalia, Anogeissus etc.
Systematics:
Cronquist placed the family under order Myrtales. Combretaceae is closely related to Myrtaceae and Rhizophoraceae.
Classification:
According to Cronquist (1981)
Kingdom: Plantae,
Division: Magnoliophyta,
Class: Magnoliopsida,
Subclass: Rosidae,
Order: Myrtales, and
Family: Combretaceat.
