The Origin and Relationships of the Araucarians. II

Abstract

The abietinean theory This theory has developed more or less gradually and can best be understood by tracing the historical sequence of discovery and the ideas of relationship that have grown out of them. i. Foremost in time and importance was the discovery that the steles of ferns, gymnosperms, and angiosperms are characterized by a leaf gap opposite the departing leaf trace. To this group was given the name Pteropsida. To the remaining groups of vascular plants the name Lycopsida was applied. This conception grew out of the investigations of the anatomy of Equisetum (27), the stem of angiosperms (28), and the structure and development of the stem in pteridophytes and gymnosperms (29). This distinction between these two great groups has been widely accepted by botanists and has formed one of the most fundamental objections in the minds of many (I6, 53) to the lycopod theory. It has been questioned by the adherents of the latter theory (54, 6i), but only in so far as to deny that a phyllosiphonic siphonostele (Araucarineae and possibly other conifers) might have arisen from a lycopod ancestry. The contention is that this type of stele is merely one of the important milestones along the evolutionary highway along which all vascular plants tend to travel. It is conceived to be in the same category as the heterosporic habit, the seed habit, and the tendency to reduce the size of the gametophytes.

22. Ruth Eicke: Beitrag zur Kenntnis der submikroskopischen Struktur der Araucariaceenhölzer

“…"The two genera Araucaria and Agathis are closely related; Agathis is probably the more recent, and within the genus Agatbis australis the highest type." Die Autoren, die die Holzanatomie in die phylogenetischen Betrachtungen einbeziehen -THOMSON und BURLINGAME -bezeichnen die Araucariaceen als cine primitive Gruppe, wobei Agathis als einfachste Form angefiihrt werden kann (THOMSON 1914, BURLINGAME 1915. Die Entwicklung cines Torus ware dann eine Spezialisierung und ein jiingeres Merkmal.…”

“…lhre Abstammung und nahe verwandtschaftliche Verbindung wird teils bei den Cordaiten, teils bei den Abietineen gesucht und schlieBlidt von SEWARD zu den Lycopodiales gelegt (SEWARD 1906). Nach reichlidiem Abwagen del' Beobachtungen und Ergebnisse von SEWARD, JEFFREY, THOMSON und zahlreichen anderen Autoren kommt BURLINGAME zu dem Schlufl, daB die Mehrzahl del' Merkmale [iir die Abstammung von den Cordaiten spricht (THOMSON 1914, JEFFREY 1905, BURLINGAME 1915. EAMES dagegen, del' etwa zur gleichen Zeit sich mit diesel' Frage besdiaftigte, bezeidmet die Gruppe als hodispezialisiert (EAMES 1913): »The Araucarineae represent a highly specialized divergent branch of the Coniferales.…”