Difference between thorny & spiky trees

Thorns and spikes are part of trees. They do have similar appearances, but they are different from each other. So, it isn’t easy to determine the difference between them by their appearance only as both almost look identical. The basic and important similarity between thorns and spines is that they are part of plants. Botanically, we can see that modified stems are thorns while modified leaves are spines. They have sharp and stiff ends, and they share the same functions. Some thorns and spines are poisonous, and others secrete chemicals such as urticating to provide a defense. These parts protect plants from animals because plants cannot protect themselves from hazardous situations.

Here we will get to know the difference between thorns & spines and their functions.

Thorns

The Thorny structures are straight, woody, and pointed modified branches of trees or plants. They have rigid extensions. Thorns are present in the axil of the leaf from where branches are developed. We can say that thorns are the axillary plant’s leaves. Thorns can be branched or simple, and some can be with or without buds. For instance, we can see branched thorns in Honeylocust ( Gleditsia acanthus). Hawrhorn has an unbranched thorn system. Alluaudia is another example of thorns where each pair of leaves bear a thorn. Some thorns, such as the Blackthorn, produce a good amount of nectar during flowering. It attracts the insect and bees to fool them that it’s a flowering plant. In many countries, Blackthorn is used for medicinal purposes. For predators, it’s difficult to consume plants bearing thorns.

Functions Of Thorns

The main reason why a plant grows thorns is protection. Thorns protect a plant from those animals that eat plants. However, they cannot protect a plant from all primary consumers because they have low arthropods defense. However, they are still worth the resources they require to be used somewhere else. Thorn damage enemies more than get hurt if enemies attack them. Most of the herbivores prefer that they can get easy food. Animals try to avoid getting hurt by the thorn of a tree and move elsewhere for a meal.

Examples Of Thorny Plants

We can find Vascular bundles(xylem, phloem) present inside the thorn, which can be branched or unbranched. They are present at the bud’s place to protect it and help it in growth. The presence of leaves is not mandatory as they can come with or without leaves. In citrus plants, the thorns are featureless and smooth. In Gymnosporia buxifolia, the thorns emerge from the axillary bud, acting as a branch. In other words, thorns are endogenous.

Toxic Thorns

Most of the thorns only hurt the skin but are not toxic, but there are some toxic thorns. Black locusts (Robinia Pseudoacacia), (Euphorbia milii), and Mimosa Pudica are examples of toxic thorn plants. Black lotus causes serious illness if an animal eats it in high quantities. Euphorbia Milli, upon the damage, secretes a toxic liquid. If it comes in contact with the skin, it can cause a severe reaction. Mimosa pudica is a sensitive plant that can cause hair loss and mild effects, such as depressed growth in animals.

Spines

Spines are the modified leaves of a plant. They bear pointed and sharp structures. Moreover, spines are firm and slender. They help the plant grow and protect it from vertebrate herbivores and other animals. They can wound the mouth and digestive organs of their body due to sharpness. Spines cover the plant and help in protection from shocking temperatures. They are present at the surface and not deeply seated. Spines can occur on the part of the leaf or may cover the entire leaf. Buds are present on the axis of spines.

Functions Of Spines

Spines have an exogenous origin. There is only one spiny organ in many species of spines. There are also some species with two or three organs in some spines. They protect their reproductive organs and non-reproductive organs from the environment. Still, reproductive organs are the most protective organ, and then they protect their leaves. The least protective organs in the spines are branches and stems. If we talk about shrubs, they protect their leaves the most. They have modified spines around their reproductive organs. Some plants have spiny wings around their leaves, stems, and shoots.

Different Categories Of Spines

We can categorize the spines into leaflet, petiolar, or stipular spines. Phoenix is an example of a leaflet spine. Ocotillo (Fouquieria splendens) is an example of Petiolar spines. It produces a spine that is present as a fusion of a lower portion of the leaf petiole and stem. Euphorbia species are examples of stipular spines. A modified stipule covers the whole structure on both sides of a bud and leaf in Euphorbia spines. The above mentioned are all examples of spines.

Stipule Spines

Stipule spines are hollow in acacia species, and it provides shelter to Pseudomyrmex ants. A plant leaf developed and converted into these spines, which contain the midrib, petiole, or secondary vein.

Cactus spines

Leaf axils are present on cactus and modified shoots or leaves. An areole is a group of spines on the cactus leaf. Cactus spines help protect predators and provide shade from the heat of the desert. It also traps the fog and converts it into water droplets for the consumption of plants. Cactus plants have shallow roots so that they can absorb water quickly. Farmers use Calicotome villosa for defense in crops.

Summing Up

Spines bearing plants have a higher rate of reproduction than other plants. Most spiny plants are present in deserted areas as they protect animals who want to consume plants as the source of water because water is difficult to get in these areas. Another reason is that there is a lack of water in deserts, and the temperature is high. Hence, they cover the surface to avoid water evaporation.