TRENDS IN SYSTEMATIC BOTANY
55
chromosome numbers, and some try to incorporate all the available experimental evidence that is applicable.
As examples of the integration of the new data with the old in forming
new classifications of plants, recent work on the grasses and the tobaccos
stands out. Prat (1936) reorganized the Gramineae after carefully
weighing, in conjunction with the standard data, the available evidence
from histology, foliar anatomy, cytology, morphology of seedlings, floral
morphology, and chemistry. Hubbard (1948) still further clarified grass
taxonomy in a proposed new arrangement of the tribes in which he
considered the evidence obtained from paleobotany, starch grains, vegetative characteristics, epidermal cells, leaf anatomy, cytology, and distribution and habitat as additional characters. The genus Nicotiana is
one of the most recent examples of an important group that has been
meticulously monographed after many years of experimental work that
has systematically revealed its phyletic organization (Goodspeed, 1954).
III. TWO CENTURIES OF FLORAS
Up until the 18th century and the time of Linnaeus, the great preponderance of botanical endeavor had been leveled at describing only
the kinds of plants found in Europe with reference to local floras,
medicinal properties, garden appeal, and other economic qualities.
Shortly before that time interest had been heightened in developing
suitable systems of classification and in attempting to circumscribe in
standard fashion the broad categories, such as the species, genus, and
family of present-day usage. When Linnaeus appeared, he made his
biggest contribution to biology by submitting an improved system of
classification based on the species. The importance of the new Linnean
concept is obvious to all working taxonomists. The reason behind its
importance is pointed out by Dobzhansky (1942) in these words: "We
marvel at the scientific insight of Linnaeus who selected species as the
basis of classification, the category of species being the only category
above the individual, which, as we know, has a high degree of objective
reality."
Under the impetus of Linnaeus's great influence, an interest in plants
on a world-wide basis blossomed forth; plant exploration was rapidly
expanded to all continents, and a long era of writing great floras was
ushered in.
Modern systematic botany takes as its starting point the production of
the first edition of Linnaeus's "Species Plantarum" in 1753. That purported to be a flora of all plants of the world, in 2 volumes totaling 1233
pages. The "Species Plantarum" went through several editions and ex-
55
chromosome numbers, and some try to incorporate all the available experimental evidence that is applicable.
As examples of the integration of the new data with the old in forming
new classifications of plants, recent work on the grasses and the tobaccos
stands out. Prat (1936) reorganized the Gramineae after carefully
weighing, in conjunction with the standard data, the available evidence
from histology, foliar anatomy, cytology, morphology of seedlings, floral
morphology, and chemistry. Hubbard (1948) still further clarified grass
taxonomy in a proposed new arrangement of the tribes in which he
considered the evidence obtained from paleobotany, starch grains, vegetative characteristics, epidermal cells, leaf anatomy, cytology, and distribution and habitat as additional characters. The genus Nicotiana is
one of the most recent examples of an important group that has been
meticulously monographed after many years of experimental work that
has systematically revealed its phyletic organization (Goodspeed, 1954).
III. TWO CENTURIES OF FLORAS
Up until the 18th century and the time of Linnaeus, the great preponderance of botanical endeavor had been leveled at describing only
the kinds of plants found in Europe with reference to local floras,
medicinal properties, garden appeal, and other economic qualities.
Shortly before that time interest had been heightened in developing
suitable systems of classification and in attempting to circumscribe in
standard fashion the broad categories, such as the species, genus, and
family of present-day usage. When Linnaeus appeared, he made his
biggest contribution to biology by submitting an improved system of
classification based on the species. The importance of the new Linnean
concept is obvious to all working taxonomists. The reason behind its
importance is pointed out by Dobzhansky (1942) in these words: "We
marvel at the scientific insight of Linnaeus who selected species as the
basis of classification, the category of species being the only category
above the individual, which, as we know, has a high degree of objective
reality."
Under the impetus of Linnaeus's great influence, an interest in plants
on a world-wide basis blossomed forth; plant exploration was rapidly
expanded to all continents, and a long era of writing great floras was
ushered in.
Modern systematic botany takes as its starting point the production of
the first edition of Linnaeus's "Species Plantarum" in 1753. That purported to be a flora of all plants of the world, in 2 volumes totaling 1233
pages. The "Species Plantarum" went through several editions and ex-