92 ANCIENT PLANTS 



themselves in alternating pairs of very small lea\'es, 

 closely pressed to the stem. The wood in microscopic 

 section shows a single row of round bordered pits 

 •on the tracheae. 



The cones are small, and the scales forming them 

 arranged in cycles. The female scales bear a varying 

 number of seeds. The pollen grain has two passive 

 male cells. The seeds when ripe are stony, with wings, 

 though in some cases (species of Juniper) the cone 

 scales close up and become fleshy, so that the whole 

 fruit resembles a berry. 



The Taxem are woody, though not great trees, 

 bushily branched. The leaves are attached spirally all 

 round the stem, but place themselves so as to appear 

 to lie in pairs arranged in one horizontal direction. 

 The wood in microscopic section shows a single row 

 •of round bordered pits on the tracheae. 



There are small male cones, but the seeds are not 

 borne on cones, growing instead on special short axes, 

 where there may be several young ovules, but on which 

 usually two seeds ripen. The seeds are big, and have 

 an inner stone and outer fleshy covering. Some have 

 special outer fleshy structures known as "arils", e.g. 

 the red outer cup round the yew "berry" (which is not 

 a berry at all, but a single unenclosed seed with a fleshy 

 coat). 



When we turn to the Cordaite^ we come to a 

 group of plants which bears distinct relationship to the 

 preceding, but which has a number of individual char- 

 acters. It is a group of which we should know nothing 

 were it not for the fossils preserved in the Paleeozoic 

 rocks; yet, notwithstanding the fact that it flourished 

 so long ago, it is a family of which we know much. 

 At the time of the Coal Measures and the succeeding 

 Permo-carboniferous period, it was of great importance, 

 and, indeed, in some of the French deposits it would 

 seem as though whole layers of coal were composed 

 entirely of its leaves. 



