82 ANCIENT PLANTS 



lily and the rose for priority. Recent work has thrown 

 no decisive light on the question, but it has undoubtedly 

 demolished the old view which supposed that the Mono- 

 cotyledons (the lily group) appeared at a far earlier date 

 upon this earth than the Dicotyledons. The old writers 

 based their contention on incorrectly determined fossils. 

 For instance, seeds from the Palaeozoic rocks were de- 

 scribed as Monocotyledons because of the three or six 

 ribs which were so characteristic of their shell ; we know 

 now that these seeds {Trigonocarpus) belong to a family 

 already mentioned in another connection (p. 72), the 

 Medullosese (see p. 122), the affinity of which lies 

 between the cycads and the ferns. Leaves of Cordaites, 

 again, which are broad and long with well-marked 

 parallel veins, were described as those of a Mono- 

 cotyledonous plant like the Yucca of to-day; but we 

 now know them to belong to a family of true Gymno- 

 sperms possibly distantly related to Taxus (the Yew tree). 



Recent work, which has carefully sifted the fossil 

 evidence, can only say that no true Monocotyledons 

 have yet been found below the Lower Cretaceous rocks, 

 and that at that period we see also the sudden inrush of 

 Dicotyledons. Hence, so far as palaeontology can show, 

 the two parallel groups of the flowering plants arose 

 about the same time. It is of interest to note, however, 

 that the only petrifaction of a flower known from any 

 part of the world is an ovary which seems to be that 

 of one of the Liliacese. In the same nodules, however, 

 there are several specimens of Dicotyledonous woods, 

 so that it does not throw any light on the question of 

 priority. 



With the evidence derived from the comparative 

 study of the anatomy of recent flowering plants we 

 cannot concern ourselves here, beyond noting that the 

 results weigh in favour of the Dicotyledons as being 

 the more primitive, though not necessarily developed 

 much earlier in point of time. Until very much more 

 is discovered than is yet known of the origin of the 



