96 STUDY OF COMMON PLANTS. 



VIII. SEAWEEDS AND THEIR ALLIES. ALG^B. 



MATERIAL REQUIRED. 



Green algse gathered in a fresh condition from different places. 

 Pains should be taken to secure the coarser, branching sorts, 

 common in running water, the fine, silky kinds that grow abun- 

 dantly in stagnant water, and the dull green felt that forms 

 on the damp ground and in pots in conservatories. 



NOTE TO THE TEACHER. The arrangement of families and higher 

 groups in the following pages is believed to indicate, as well as a lineal 

 arrangement can, their natural succession, and is that adopted by modern 

 botanical writers. In most preparatory schools, however, certainly in 

 those not fully equipped for microscopic work, the best results will be 

 attained by following a somewhat different order. After studying the 

 organs of flowering plants, it will be found advantageous to pass at once 

 to the Coniferae, then to the early flowering families of phanerogams, 

 taking them in the order that is most convenient, which will be deter- 

 mined chiefly by time of flowering and abundance of material. As a rule, 

 the cryptogams should be studied later, although in schools provided with 

 a full laboratory outfit the order followed in the book may be the best. 



No attempt is made to treat all families alike. The aim is simply to 

 help the student in every case to ascertain existing facts and their mean- 

 ing. Observation should constantly be directed to the differences and 

 resemblances by which various degrees of relationship are determined. 

 The exercises on the Coniferse and Ranunculacese will serve to indicate 

 the prominence that may properly be given to this idea, which forms the 

 basis of vegetable morphology. On the other hand, observations of 

 distribution and physiological adaptations, too much neglected hitherto, 

 should receive their full share of attention. It is essential that careful 

 descriptions of the plants examined should be written, and that these 

 should be accompanied by sketches. The number of these will vary 

 according to circumstances and the judgment of the teacher, but they 

 are by no means to be omitted. 



