PLANT FAMILIES AND HIGHER GROUPS 7 



the specific part of the name. Both parts are required to form the 

 name of the species. Alba, nigra, etc., bj^ themselves are not names. 



11. The authority. It has sometimes happened that diiferent 

 botanists have given different names to plants of the same species, 

 and the same name to plants of different species. To avoid any un- 

 certainty as to just what plant is meant it is customary in technical 

 botanical writings to place after a specific name tlie name (usually 

 abbreviated) of the person or persons who first gave to the plant 

 the name adopted. For example, if we write Gy psophila fastiqiata L., 

 it is plain to a botanist tliat the species so called by Linnaeus is the 

 one intended. Linna?us in this case is called the authority for the 

 name. In popular or elementary books, like the present, authorities 

 are usuall}'^ omitted for the reason that only plants well known to 

 botanists are apt to be mentioned, and the authorities for these may 

 readilj' be found in the more technical botanies in case of need. 



12. Plant families and higher groups. On the same 

 principle -that similar species form a genus, similar genera 

 are grouped into a family; and families which have certain 

 fundamental points of similarity are associated to form still 

 more inclusive divisions of the vegetable kingdom. Thus 

 the oaks (Quercus), chestnuts (Castanea), beeches {Fagus), 

 and other trees which agree in having their flowers in tassel- 

 like clusters, and their nut-like fruits held in something corre- 

 sponding to a beech-bur, make up the beech family or Fagacece.. 

 The poplars (Populus) and wallows (Salix) which also have 

 tassel-like flower-clusters but only small seeds bearing slender 

 silky hairs, constitute the willow family or Salicacea'. Lilies 

 and similar plants compose the lily family Liliacece; palms, 

 the palm family, Palmacece; pine-like plants, the pine family, 

 Pinacece, and so on. Plants like cabbage and mustard wnth 

 flowers of cross-like form belong to the mustard family Cru- 

 ciferoB. i 



So closely similar to the Fagacece are the members of the 

 birch family, Betulacece, that botanists find it convenient 



1 It will be noticed that tho botanical name of the families is formed 

 usually by adding the termination aceiv to the main part of the name of 

 a typical genus of the family. This termination corresponds to the 

 English suffix aceous, meaning "having the qualities or characteristics 

 of." The name is thus of adjective form, the noun plantce being under- 

 stood. Hence the full name of the willow family would be Ptantw 

 salicacecp, meaning salicaecous for willow-like) plants. In a few cases 

 like Cruciferte (from L. crux, cruris, a cross; fcro, 1 bear) the name ex- 

 presses a peculiarity of the whole family. 



