XXviii INTRODUCTION. 



with the petals, or free from them. In ours they are free. Lastly, whether 

 they are united into a tube, or in clusters, or are all separate. In ours they are 

 sre united in five clusters, and the sepals are deciduous. This brings our plant 

 to the natural order, TILIACE^E, 59, the number referring to the page of the 

 Flora where the order is described. 



Turning to that page, and comparing our plant with the character of the 

 order, we notice their agreement. 



We then proceed to find the name of the genus. This is readily done, in this 

 instance, by comparing the plant with the two genera comprised in this order. 

 With the first it will be found to agree in every particular, 'and therefore we 

 need not carry it further. We find, then, the plant in question to be a species 

 of the genus TILIA, so named by Tournefort, and commonly called Linden or 



Again, suppose the plant under consideration to be the common Bear-Grass. 

 Having flowers, it is, of course, Phcenogamous. But, cutting across the stem, we 

 find, in the place of pith, wood, and bark, a white mass of cellular tissue, stud- 

 ded with minute points, which are the ends of the divided threads of woody 

 fibre ; the veins of the leaf run parallel from the base to the apex ; the floral 

 envelopes are in two rows of three each ; and the embryo, if examined, will be 

 found to have but one cotyledon. In these respects, our plant differs widely 

 from the Class of Dicotyledonous Plants, and we therefore turn to its alterna- 

 tive, the CLASS of MONOCOTYLEDONOUS PLANTS, on page xxxvii. of the Anal- 

 ysis, which, we observe, includes plants possessing these characters. 



Our plant, having the floral envelopes double, and not glumaceous, falls 

 under the second heading, marked with two stars ( * * ). 



Proceeding as in the former example, and carefully comparing the plant with 

 the analysis that follows, we see, first, if the ovary is adherent with, or free from, 

 the perianth. In ours it is free. Then, if the perianth is single, or double. In 

 ours it is double. Then, if the calyx and corolla are alike or unlike. In ours 

 they are alike. Then, if the leaves of the perianth are glume-like, or otherwise. 

 In ours they are not glume-like. Then, if the leaves are netted-vcined or par- 

 allel-veined. In ours they are parallel-veined. Then, if the capsule is 1-celled, 

 or 3 - 6-celled. In ours it is 6-celled. Lastly, if the anthers are introrse or ex- 

 trorse. In ours they are introrse. 



This brings us to the natural order LILIACE^E, described on page 480 of the 

 Flora. It contains ten genera, belonging to three tribes, the characters of which 

 are briefly given in the Synopsis. Our plant, by its capsular fruit, the separate 

 divisions of the perianth, and leafy stem, comes under the third tribe, TCLIPA- 

 CE/E. Of the two sections, marked with a star ( * ), our plant belongs to the 

 second ; having a Palm-like stem. No. 10, Yucca, alone remains ; and to it 

 our plant must belong. 



Turning to page 485, where this genus is more fully described, we find it to 

 embrace four species, divided into two sections based upon the character of the 

 stem and capsule. The short stem (excluding the scape) and dry capsule of 

 our plant belong to the former. It contains but one species, Y. filamentosa, L., 

 which we therefore find to be the botanical name of the plant in question. 



