deteriorated in Loranthaceae) ; and though the loss of cambium and the arboreal form 

 is commonly expressed among Angiosperms, as organisms give ' quicker returns ' in 

 reproductive maturity, no living Gymnosperm is ' herbaceous '. 



From such elementary considerations it follows that only the minor headings of 

 systematy, expressing the smallest variations, represent the features still sufficiently 

 plastic and open to alteration in modern lines of progression. Broader generalizations 

 delimiting large groups cover still older features of organization now fully established, 

 so far as one can see, for all future time. Systematy thus begins to acquire a phyletic 

 value, and demands a phyletic consideration of the events of a remote history. Every 

 little detail, however apparently meaningless, may have a complex story behind it, 

 successful interpretation of which may throw an unexpected light on the life-problems 

 of an ancient world. 



In actual fossil-remains impressions of shoots and cones can be reliably traced 

 to the Lower Cretaceous. Araucarineae were probably cosmopolitan at this epoch, 

 and were but little different in the Palaeozoic. Pine-cones with normal apophysis 

 and central umbo, of the highest grade of construction, and of average dimensions, 

 occur in the Lower Cretaceous, representing a range of more than one hundred million 

 years. Cones apparently similar to those of Cednis occur in the Upper Cretaceous, 

 as others suggestive of Sequoia and unmistakably Taxodinous forms are found in early 

 Tertiary deposits of probably fifty million years ago. (Seward, 1919, p. 389.) 



The environment which produced the Pine-cone, as the most complex construction 

 of the Pinoid series, was that of ages at least antedating the Lower Cretaceous, and 

 the extreme xeromorphic organization characteristic of the leading types of modern 

 Gymnosperms has no necessary relation to the climate of the present day, but was 

 settled many millions of years ago, and is not lightly changed. Thus Larioc, though 

 secondarily deciduous, still retains the anatomical peculiarities of the Cedrus-type of 

 foliage-needle, differing only in the reduced sclerosis of identical tissue-units. The 

 xeromorphic specialization gained at a remote geological epoch now enables the plants 

 to survive in inferior biological stations, under pressure of competition with higher 

 Angiosperms, but they will not change in these essential respects under the most ideal 

 conditions of cultivation. 



The fact that even generic characters may be referred to distances of fifty to 

 a hundred million years ago implies that still wider group distinctions are much older 

 and beyond recall. Facts of modern geographical distribution have little bearing on 

 the inter-relations of recent types. The four conventional series of Pinoids, for example, 

 acquire phyletic value only from purely morphological deductions, and the common 

 ancestry of Pinoids and Taxoids remains a matter of pure speculation. The few 

 surviving members of the Araucarineae present a coherent and isolated group of 

 remote relationship. The Abietineae are fairly connected in the close parallelism 

 of their cone-scale cones ; the Cupressineae by their peculiar vegetative habit. On the 

 other hand the Taxodineae remain a wholly empirical set of archaic and vestigial 

 forms of probably very distant relationship. 1 



In determining the main lines of classification two standpoints may be illustrated, 

 as based on : 



I. The somatic organization of the sporophyte generation, as expressing the mechanism 



of autonutrition of the successful individual life in : 

 (a) The relation of the external form to light and air-supply. 

 (/?) The internal organization of the photosynthetic and transpiring leaf-lamina. 

 (Y) The anatomical organization of the conducting vascular tissue of the stem 



(including timber), which provides the supplies of ions of nitrogen and 



phosphorus and food-salts. 



II. The Reproductive Organization by means of which the life of the race is 



continued and wastage is compensated, as expressed in : 

 (a) The output of wind-borne spores (microspores only), still necessarily 



enormous. 



(/?) The wastage of sexual cells (reduced nearly to a minimum), 

 (y) The wastage of the seed-stage in dispersal and in germination, in relation 



to both factors of environment and competition with other plants. 



1 Seward (1919, p. 124) ; Saxton (1913, p. 253) ; Coulter and Chamberlain (1910, p. 303). 



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