Understanding Artificial and Phylogenetic Systems of Classification in Botany

Introduction to Artificial System of Classification

The artificial system of classification in botany, primarily developed by Carl Linnaeus, is a method where a limited number of characters or traits are used as the basis for categorizing plants. This system is characterized by its simplicity but often overlooks the deeper genetic and evolutionary relationships between different plant species.

The Basis of Linnaeus' Artificial System

Linnaeus was a pioneer in using specific floral characters to classify plants. He devised a system where the presence or absence of certain features would determine plant placement. His artificial system was based on twenty-four floral classes, each defined by various aspects:

Number of stamens in a flower Insertion of floral parts into the thallus Arrangement, adhesion, and distribution of stamens Nature of the anther and filament and their arrangement

While this system was groundbreaking, it inherently limited the classification by basing it on a narrow set of criteria, often ignoring other evolutionary or genetic traits.

Historical Development of Artificial Classification

The earliest version of an artificial system can be traced back to Theophrastus, a Greek botanist from the 3rd century B.C., who classified plants based on form and texture. Other notable contributors to artificial classification include:

Andrea Caesalpino (1519-1603) who divided plants into woody and herbaceous species. John Ray (1628-1705) who differentiated between Imperfectae (non-flowering) and Perfectae (seed-plants). Carl Linnaeus (1707-1778) who developed the most advanced artificial system, primarily based on floral characters, and is often referred to as the 'father of systematic botany'.

These early attempts at classification laid the groundwork for more complex systems to follow, but the artificial system remains marked by its simplicity and lack of predictive value due to its limited scope.

Phylogenetic Systems of Classification

The publication of Darwin's 'On the Origin of Species' in 1859 significantly influenced the development of new classification systems in botany. Phylogenetic systems, in contrast to artificial systems, focus on the evolutionary history and relationships between plant species.

The Engler-Prantl System

The most widely accepted phylogenetic classification system is the Engler-Prantl system, developed in the late 19th to early 20th century. It categorizes plants based on their evolutionary sophistication, from simpler to more complex forms. This system is organized into two major divisions:

Division I - Gymnospermae: Further divided into seven classes including Cycadofilicales, Cycadales, Bennettitales, Ginkgoales, Coniferales, Cordaitales, and Gnetales. Division II - Angiospermae: Divided into two classes:

Angiospermae Sub-Categories

Class I - Monocotyledoneae: Includes 11 orders and 45 families. Class II - Dicotyledoneae: Further sub-divided into two sub-classes:

Subclass Division of Dicotyledoneae

Subclass 1 - Archichlamydeae: Includes 33 orders and 201 families. Subclass 2 - Metachlamydeae: Includes 11 orders and 60 families.

The Engler-Prantl system provides a more comprehensive and evolutionary-based approach to plant classification, placing greater emphasis on genetic and ancestral relationships over purely morphological traits.

Conclusion

The transition from artificial to phylogenetic systems reflects a significant shift in botanical taxonomy. Artificial systems, while valuable in their simplicity, often lack the depth needed to understand the rich evolutionary narrative of plant life. Phylogenetic systems offer a more nuanced and sophisticated approach, providing a clearer picture of plant relationships and evolutionary history.