264 THE TEACHING BOTANIST 



since it so nearly represents a theoretically primitive flower, 

 *'. e. one consisting of stamens, or pistils, and a nectar gland ; 

 the latter is theoretically the first accessory part of a flower to 

 appear, and the most important part in adaptation to insect 

 visits ; the color develops later to show where the nectar is, and 

 brings with it the need for a color-carrier, which office is 

 assumed by some of the stem leaves, originating the corolla. 



There is much doubt as to the position of the Monocoty- 

 ledons. By some they have been considered as a side 

 branch of Dicotyledons, but the weight of evidence at the 

 present day places them in the ancestral line of the Dicoty- 

 ledons, and derives them through the low water-plants from 

 the heterosporous higher water-ferns. The division into Ape- 

 talae, Polypetalse, and Gamopetalae is not natural, but is 

 convenient from an ecological point of view. The teacher 

 will, of course, keep before the students the part played by 

 adoption of insect pollination in development of the corolla, 

 and of increasing specialization for insect visits in the devel- 

 opment of the gamopetalous condition. The teacher should 

 use in classification the Engler and Prantl system employed 

 in the most modern books ; it is much more natural than 

 the Bentham and Hooker system largely employed hitherto. 

 The aim of the teacher in selecting materials for study in 

 this division should be to represent the leading groups and 

 families, as they are given in the best modern books, as, for 

 instance, in Campbell's " Evolution," and in Strasburger's 

 "Text- Book." Of course, at this time naturally comes the 

 use of manuals for identification of species. As I have already 

 said, however, I do not think the time of all members of the 

 class should be taken for this, but extra voluntary classes 

 should be formed of those especially interested in the sub- 

 ject. Of great profit, too, are field excursions, when atten- 



