Barber. — Cupressinoxylon vec tense. 331 
affinity of plants. The independence of these systems was 
first insisted upon by Goppert, and to him therefore we owe 
our first real advance in the subject 1 . 
Goppert instituted certain classes or types of wood which 
he termed c genera, 5 but which, so far from being synonymous 
with the genera of systematists, frequently united members 
of the most widely separated groups. 
Goppert’s genera, emended by Kraus 2 , form the basis of 
all recent classifications of existing and fossil Coniferous 
woods. These may be arranged according to the following 
types : — 
1. Araucaria Type. Araucarioxylon. Bordered pits small, 
touching, usually mutually compressed, several rows in each 
tracheide, the pits in adjacent rows placed alternately. 
2. Cupressus and Abies Type. Cupressinoxylon and Cedro - 
xylon. Bordered pits separate, in one row, or, if in more 
than one, the pits of different rows opposite one another, 
resin-canals absent, but strands of wood-parenchyma contain- 
ing resin. In Cupressinoxylon the resin-parenchyma is 
abundant, in Cedroxylon scarce or absent. 
3. Pinus Type. Pityoxylon. Bordered pits as in 2, resin- 
ducts with sheaths of wood-parenchyma among the tracheides 
and in the medullary rays, no separate wood-parenchyma 
strands present 3 . 
4. Taxus Type. Taxoxylon. Bordered pits and wood- 
parenchyma as in 2, no resin-ducts, tracheides with well- 
marked spiral thickenings. 
Of these four types the first two are far more frequent 
in the fossil condition, the Araucarian with its allies extend- 
ing from the Devonian to the present time, while Cupressino- 
xylon and Cedroxylon are more characteristic of the Secondary 
and Tertiary periods. 
1 Goppert, De Coniferarum structura anatomica, Breslau, 1841. 
2 Goppert, Monographic der fossilen Coniferen, Leiden, 1850; Kraus, Mikro- 
scopische Untersuchungen iiber den Bau lebender und vorweltlicher Nadelholzer, 
Wiirzburger Naturwissenschaftliche Zeitschrift, v, 1864. 
3 Schroeter, Untersuchungen iiber fossile Holzer aus d. arct. Zone, FL fossil, 
arct., Oswald Iieer, vi, Zurich, 1880, 
