HOW TO USE THE KEY AND THE FLORA. XI 



we have three subordinate headings, marked by one, two, and 

 three asterisks, respectively. Thestamensareolearlyinserted 

 on the calyx, and so our plant must be found under the 

 heading marked **. "Without hesitation, we refer it to the 

 Order Eosace^. Turning to page 62, we find seventeen 

 Genera to select from. A very little consideration will show 

 us that No. 11, Pragakia, is the Genus we must fix upon. 

 Eeferring to page 69, we have to choose between two species, 

 Virginiana and vesca, and the choice is found to depend upon 

 such obvious characters as to furnish no difficulty. 



The leaves of Blue Flag are straight- veined ; the parts of the 

 fiower, also, are in threes. We therefore decide that the 

 plant is Monocotyledonous, and on turning to page xxii, we 

 find three Divisions of Monocotyledons. The Flag clearly 

 belongs to the Petaloideous Division. Then, is the peri- 

 anth superior or inferior ? Clearly the former. Next, are the 

 flowers dioecious or perfect? Clearly perfect. And as the 

 flower has three stamens, it must belong to the Order 

 Iridaoe^, described on page 235. The Genus is at once seen 

 to be Iris, and the Species is determined without diifioulty. 



TheOat-tailFlagisalso manifestlv Monocotyledonous, from 

 the veining of the leaves. But it is not Petaloideous. The 

 flowers are collected on a more or less fleshy axis at the top 

 of a scape. It therefore belongs to the Spadiceous Division, 

 in which there are four Orders. The only practical question 

 is, whether our plant belongs to Arace^ or TvPHACBiE. On 

 the whole, we choose the latter, and find our decision con- 

 firmed on reading the fuller account of the two Orders on 

 pages 217 and 219. The Genus is immediately seen to be 

 Ttpha, and the Species latifoUa. 



These examples need not be extended here ; but the 

 beginner is recommended to run down, in the same manner, a 

 few plants whose names he already knows. If successful in 

 these attempts, he will naturally acquire confidence in his 

 determinations of plants previously unknown to him. 



