Morphology Of Angiosperm of Class 11
The life-span of angiospermic plants is highly variable. Herbaceous plants like pea and gram live only for few weeks. Most common trees live between 50-200 years. Of the long lived trees, one is peepal (Ficus religiosa) having a life-span of 2000-3000 years. Bodhi tree of Gaya (Bihar) is about 2500 years old.
- Smallest angiosperm : Wolffia (0.l mm diameter). Aquatic Lemma has a diameter of 0.1 cm. Arceuthobium is another small angiosperm plant which is parasitic over Pinus and other trees.
- Tallest plant (angiosperm) : Eucalyptus regnans (114 metres or 375 feet height).
- Tree having largest crown : Banyan tree (Ficus benghalensis).
❒ Majority of angiospermic plants are autotrophs (plants which can synthesize their own organic food from inorganic substance e.g., CO2 and H2O). There are, however, many plants, which draw their organic food from different sources and are called heterotrophic plants. They are of three types:
- Saprophytes : They obtain their nourishment from dead organic matters. Angiospermic saprophytes are also called humus plants. They are non-green and bear scaly leaves e.g., Indian pipe (Monotropa), bird’s nest orchid (Neottia), chain orchid (Pholidota), coral root (Corallorhiza), etc.
- Parasites : These are the plants, which obtain their nourishment partially or wholly from other living organisms called hosts by their sucking roots. Common examples of different types of phanerogamic parasites are as follows:
- Total stem parasites e.g., dodder (Cuscuta reflexa), Arceuthobium, etc.
- Partial stem parasites, e.g., Viscum, Loranthus, etc.
- Total root parasites e.g., broomrape (Orobanche indica), Aeginetia indica, etc.
- Partial root parasites e.g., sandalwood tree (Santalum album), Striga lutea.
- •Carnivorous plants: These are predator plants which capture insects. They often grow in nitrogen deficient soils. They are green in colour and prepare their own carbonaceous food, while they partially depend on insects and other animals for nitrogenous food. Some examples are sundew (Drosera), venus fly-trap (Dionaea), bladderwort (Utricularia), butterwort (Pinguicula), Aldrovanda, Nepenthes (The Asiatic pitcher plant) Sarracenia (The north-American pitcher plant).