182 CHARACTERISTICS OF PLANTS. 



"We will now take a more difficult illustration viz., that of the Stinging Nettie 

 (Urtica). We first notice that the flower is deficient in stamens or pistils, and thence 

 that it is not bisexual. "We then examine other flowers, and ascertain that this is not 

 a mere coincidence, but is universal ; and, further, that all the flowers are unisexual, 

 and that on the same tree there are flowers only male, and others only female. Thus 

 we refer the plant to the class Monoecia. "We now select a male flower that is, one 

 having stamens only ; and finding that there are four stamens, we refer the plant to the 

 order Tetrandria. In this order there are but five genera, and of these one is a tree 

 the Alder and another is the common Box (Buxus), with both of which the student 

 will be familiar, and know at once that they cannot refer to the plant in question. 

 Moreover, two others, Littorella and Eriocaulon, are found, by the description of their 

 solitary genus, to grow in lakes and marshy places ; and as his plant grew on a bank, or 

 on some waste diy land, he may exclude them, and thus find that he is referred to the 

 only remaining genus, that of Urtica. This careless mode of exclusion will not, how- 

 ever, suffice beyond the point of directing immediate attention to the remaining genus, 

 and therefore he will at once proceed to compare the description of the Urtica with the 

 characters of the plant in his hand. The following description will suffice to indicate 

 the genus Urtica : 



" Barren (or male) flower. Calyx of four roundish, concave, equal leaves. Petals 

 none. Nectary central, cup-shaped. Filaments four, awl-shaped, spreading, as long 

 as the calyx ; anthers roundish, two-lobed. Fertile (or female} flow&r. Calyx inferior, 

 of two roundish equal leaves. Corolla none. Ovary egg-shaped. Style none. Stigma 

 downy. Seed one, naked, egg-shaped, somewhat compressed, polished, embraced by 

 the permanent calyx." 



The term nectary is here used in the indefinite sense in which Linnaeus employed 

 it, when he assembled very various structures, situate at or about the base of the ovary, 

 under that appellation, and in the sense in which it is still used by systematic works 

 on classification. It is not the true nectary found upon the short claw of the petal of 

 the Kanunculus, since the Urtica has no petals. 



The determination of the species is not difficult, since there are but three species of 

 Urtica, all of which have venomous stinging or secreting hairs, and opposite leaves, 

 and the distinguishing features are referred to only two or three points. Thus we 

 will suppose that the plant under examination is the small Nettle, or Urtica urens, and 

 that the following description will indicate its characters : 



" Leaves opposite, broadly elliptical, with about five longitudinal ribs ; clusters 

 simple. From one to two feet high ; bright green, with venomous stings. Annual; 

 flowers from June to October ; grows on cultivated ground and waste places." 



Having given these two illustrations, we think that the attentive student will find 

 no difficulty in proceeding with the examination and classification of plants ; but we 

 think it needful to append one caution. Do not be discouraged if you have difficulty 

 in referring an unknown plant to its proper place amongst the genera and species ; but 

 having given due attention and failed, lay the plant aside, or invite the assistance of 

 some one who may have made further progress in the science. There is no royal road 

 to learning, and the first steps will ever be toilsome and difficult ; but, as the student 

 proceeds, he will find that the difficulties gradually and insensibly recede, until, in a 

 short time, he wonders that he ever regarded them for a moment. Do not at first 

 fatigue the mind, and discourage the spirits ; but be assured that you, like others, will 

 overcome them. 



