Such plants variants are known as Biotypes. All the biotypes are similar genetically but are different morphologically. The difference in the morphology is due to the abiotic factors like temperature, soil quality, climate, water availability etc. The difference in the abiotic conditions is due to the altitudinal gradient. Therefore the plant species show differences in morphology due to the altitude gradient.
When these plants are grown in similar conditions, there is no difference in the abiotic factors and hence all are similar in morphology.
