SYSTEMATIC BOTANY. 89 



semblance in flowers, fruit, etc. They are, therefore, grouped 

 together and constitute a family called Leguminosae. Others, 

 as the Ironweeds (Vernonia), Thistles (Carduus), Dandelion 

 (Taraxcwum), Hieracium, Lactuca, etc. — characterized by 

 having the flowers in an involucrate head and united an- 

 thers — form the family Compositae. In like manner, that is 

 by grouping more or less closely related genera, other fami- 

 lies, as Ranunculaceae, Cruciferae, Labiatse, Gramineae, etc. 

 are formed. Larger groups, or Orders, are formed of fami- 

 lies and still more comprehensive are the so-called 

 Classes. 



5. The system of nomenclature, perfected by Linnaeus, and 

 used since his time, is binomial ; that is, every plant is desig- 

 nated by a double name — the name of the genus followed by 

 the name of the species, both being Latin or Latinized words. 

 Thus tbe botanical name of Black Walnut is Juglans nigra 

 L. ; of Sugar Maple, Acer saccharum Marsh. ; of Burr Oak, 

 Quereus macrocarpa Mx. When a variet)' is to be designated 

 a trinomial is used ; thus, a variety of the native Hydrangea 

 is called Hydrangea arborescens kanawhana jNIillsp. The spe- 

 cific name is generally an adjective, as canadensis (in Sangui- 

 naria canadensis L.) ; sometimes it is an old substantive as 

 stramonium (in Datura stramonium Ij.), or the name of a per- 

 son as purshii (in Phacelia purshii Buckley). The generic 

 name is a substantive, and may be the old classical name, as 

 Platanus, Acer, Quereus ; a name formed from Latin, Greek 

 or other words, as Trifolium (Lat. tri, three; folium, leaf), Zea 

 (Gr. Zqfi, to live). Datura (Arabic Tatorah) ; or the name of a 

 person, as Claytonia (after John Clayton, an early botanist of 

 Virginia) ; Linnaea (after Linnaeus, the immortal Swedish bota- 

 nist, born 1707, died 1778). The abbreviation of the author's 

 name is also added when botanical names are written. Thus, 

 L., Marsh., and Mx. in the names above are for Linnaeus, Mar- 

 shall and Michaux, who described and named the respective 

 species. 



6. The two most comprehensive groups in the vegetable 

 kingdom are the Seed-bearing plants (Phenogams), and the 



