182 ACADEMIC BOTANY. 



The 15th Class has 2 Orders : 



1. Siliculosa, fruit a siliole — Shepherd's Purse (Fig. 200, C) ; 



2. Siliquosa, fruit a silique— Wall-flower (Fig. 200, A). 



The i6th, 17th, and i8th Classes have their various Orders dis- 

 tinguished like those of the first Thirteen. 

 The igth Class has 6 Orders; 



1. Polygamia equates, composite heads, florets all monoclinous — 

 Dandelion, Artichoke (Fig. 214) ; 



2. Polygamia superfiua, composite heads, disk-florets monoclinous, 

 ray-florets female — Chamomile ; 



3. Polygamia frustranea, composite heads, disk-florets monoclinous, 

 ray-florets neutral — Blue-bottle ; Jerusalem Artichoke (Fig. 95) ; 



4. Polygamia necessaria, composite heads, disk-florets male, ray- 

 florets female — Marigold (Fig. 143) ; 



5. Polygamia segregata, several small heads, each with a partial in- 

 volucre, collected in a compoiind head with a large common involucre- 

 Everlasting ; Edelweiss ; 



6. Monogamia, flowers single, not in heads, but with syngenesious 

 anthers — Lobelia, Violet, Balsam. 



The 20th, 2ist, and 22d "Classes have Orders distinguished like 

 those of the first 13 Classes. 

 The 23d Class has 3 Orders: 



1. Moncecia, flowers bisexual and unisexual on the same plant — 

 Maple ; 



2. Diceeia, flowers bisexual and unisexual on separate plants — Ash ; 

 8. Trioecia, flowers bisexual, male and female, each type on a sepa- 

 rate individual — Carob-tree. 



The 24th Class has 5 Orders : 



1. Perns; 2. Mosses; 3. Liverworts; 4. Seaweeds; 5. Mushroovis. 

 (Copied from Mirbel's Physiologie Vegetate.) 



443, The Artificial System, we see, places the Indian Corn and the 

 Walnut in the same class, though one is an Endogen and the other an 

 Exogen. And not only do we find this arbitrary grouping of distinct 

 and alien types, but also the separation of genera which in nature are 

 nearly related. The Sage, for example, naturally belongs in the same 

 Family with the Mint, yet the Artificial System puts it with the 

 Olive, with which it has nothing in common except exogenous growth 

 and two stamens. 



