Distribution of Alocasia in the Philippines
Based on current observations, the Alocasia genus is widespread and thought to be found naturally in all of the major islands of the Philippines. Other species groups are only limited to certain areas or islands in the country.
Habit and Environment
The size and habit of Alocasia are usually dependent on the species' evolutionary adaptation to their natural environment. They are found in a wide range of habitats, from limestone slopes and walls, rocky substrates, thick layers of decomposing forest litter, sandy soil, coarse clay, in elevations as low as beach forests or streams and rivers to the highest mountains. Small herbs in this genus are usually found with their long stem (also known as rhizomes) being decumbent or creeping horizontally on the ground's surface, while the largest thick-stemmed pachycauls (e.g. A. macrorrhizos & A. portei) are usually able to support themselves vertically.
Morphology
Alocasia, despite their very typical morphology can have multiple variations in a single species. Certain features or vegetative parts of some Alocasia species are distinct enough that it can be used to distinguish species from one another. A single look at the signature peltate and shield-like leaves of A. clypeolata; bat-shaped leaves of A. nycteris; dark and velvety leaves of A. micholitziana; striped or zebra-like petioles of A. zebrina; pubescent petioles of A. maquilingensis, and many others can easily help you identify them. Some obscurely similar ones however, like the natural variations of A. heterophylla & A. boyceana, and A. scalprum & A. sinuata can be difficult to distinguish from one another unless you take a closer look of their reproductive or floral structure.
For a more detailed analysis of Alocasia morphology, visit this page
For a full list of all the Alocasia species, visit this page