2 THE NATURE OF BOTANY 
Morpuovoey considers the form and structure of plants. It 
considers the forms of plant bodies and the organs and tissues 
which compose them. Morphology studies the structure of 
roots, stem, leaves, buds, and flowers, and establishes the rela- 
tionships of organs. Morphology not only considers the more 
complex plants but also the simpler ones, and traces the develop- 
ment of plant structures through the different plant groups. The 
phase of Morphology in which the development of the more 
complex plants from the simpler ones is studied, is called Plant 
Evolution. When Morphology is concerned with the micro- 
scopical study of the finer structures of plants, then it is called 
Anatomy, and if the study is mainly concerned with the structure 
of the cell, then it is called Cytology. Anatomy and Cytology are 
often spoken of as Histology. Another phase of Morphology is 
Embryology which, as the term suggests, is the study of the 
embryo, or the study of the plant during its formation in the seed. 
Piant Puysio.oey studies the functions of plant structures and 
the relation of these functions to light, temperature, air, soil, etc. 
It treats of how the plant lives, respires, feeds, grows, and re- 
produces. In the study of Plant Physiology we learn how plant 
food is made and transported, and how plants grow. As a basis 
for the study of Plant Physiology, one must have a knowledge 
of the Morphology of plants and also a knowledge of Chemistry 
and Physics. 
Piant PatHo.oey treats of plant diseases. In this subject one 
learns the disease producing plants and how they affect the plant 
diseased. In the study of Plant Pathology, in order to know how 
the diseased plant is injured, one must know the nature and 
function of the tissues attacked. This means that one should 
know Morphology and Plant Physiology. Furthermore, in order 
to know how the disease producing form attacks other plants and 
propagates itself, one needs to know its Morphology and Physi- 
ology. 
Puant Ecoxtoey considers plants in relation to the conditions 
under which they live. Some plants can live on a dry hill top, 
while others can live only in moist, shady places. Some can live 
in colder regions than others. Some plants, like many of the 
weeds, can thrive when crowded among other plants, while some 
like the Corn plant can not. Marshes, bogs, forests, sandbars, 
etc., all have their characteristic plants. One set of plants often 
