Apbil 29, 1910] 



SCIENCE 



649 



as the plants grow in the garden or the 

 accompanying greenhouse. Because they 

 can be observed continuously the student 

 gains a familiarity with them and their 

 phenomena which is not possible from a 

 single contact with them, when they are 

 brought out once a year, in a laboratory 

 course. 



2. The garden and greenhouse have an 

 important use as a source for the material 

 needed in instruction and research, in labo- 

 ratory and herbarium. 



3. The existence of a garden insures the 

 presence of propagating grounds, tools and 

 a trained gardener, all of them necessary 

 to the carrying on of researches in plant 

 breeding or other work involving extensive 

 cultures, such as are often made in studies 

 of variation and experimental morphology. 



4. Not the least important feature of 

 a garden, especially one on a university 

 campus, is that it shall prove attractive 

 from its design and the plants in it, entirely 



.aside from its scientific interest. 



I shall, from this on, make casual refer- 

 ence only to the last three of these func- 

 tions, but shall dwell more fully on the 

 first, i. e., the use of a garden in botanical 

 instruction. This is, I believe, the func- 

 tion which chiefly determines the arrange- 

 ment of most botanical gardens now in 

 existence, the only other potent influence 

 being, perhaps, the artistic one. 



The botanical facts and principles that 

 can well be illustrated in a botanical garden 

 may be grouped under the following heads : 

 (1) plant structures, (2) plant phylogeny, 

 (3) plant activity or physiology, (4) plant 

 ecology, (5) floristic plant geography, (6) 

 economic plants. "We may now take these 

 up in the order mentioned. 



1. Plant structures may be illustrated by 

 examples, first, of vegetative organs, in 

 their various modifications, and secondly 

 by examples of reproductive organs, such 



as those for vegetative multiplication, for 

 asexual reproduction, and for sexual repro- 

 duction, including such accessory repro- 

 ductive organs as flowers and fruits. 



2. Plant phylogeny may be illustrated by 

 the natural system of Engler, as a modern 

 interpretation of the kinship of plants, also 

 by selected examples of older ' ' natural sys- 

 tems ' ' of historical importance, such as the 

 systems of Jussieu, Braun and Eiehler. 

 Finally, examples of plant breeding may 

 be made to illustrate the means of origin 

 of new types of plants, such as sports, 

 mutants and hybrids. 



3. Types of plant activity that may be 

 readily illustrated in a garden are: first, 

 those connected with growth— showing its 

 rate, direction and seasonal variation ; sec- 

 ondly, sleep movements; thirdly, move- 

 ments of leaves of compass plants; fourth, 

 the movement of irritable or sensitive 

 leaves; fifth, and finally, those movements 

 of the flower, or its parts, which aid in the 

 process of pollination, of which many inter- 

 esting examples may be shown. 



4. In plant ecology we may well illus- 

 trate certain important habitat-relations 

 and growth-forms. Those that can be most 

 .satisfactorily shown are chiefly relations to 

 edaphie factors, though the alpinum and 

 the greenhouse give some opportunity of 

 suggesting relations to climatic factors. 

 Other ecological facts may be illustrated 

 by examples of plant communities. Under 

 this head, when enough ground is available, 

 may be shown plant formations, chiefly 

 native ones, as forest, bush, meadow, etc. 

 Finally, ecological guilds, or types of sym- 

 bionts, may be illustrated by lianes, epi- 

 phytes, saprophytes and parasites. This 

 latter series takes but little space in the 

 garden, but much ingenuity is required to 

 make them develop typically. 



5. Floristic plant geography may per- 

 haps be best illustrated not merely by 



