282 



GYMNOSPERMS 



[ 



scale and magnified 8 diameters, shows the general range of size and 

 appearance. 



The leafy character is quite pronounced in Araucaria cunning- 

 hami and Picea excclsa, and in Dacrydium datum it is scarcely dis- 

 tinguishable from the foliage leaf; while in many 

 it is more reduced, and in some there is no more 

 resemblance to the original leafy blade than in 

 the cycad, Zamia. 



The sporangia arc borne on the abaxial face 

 Wm ' il 1 °^ ^^^ sporophyll. However, Hagerup"* claims 

 that in Dacrydium datum, a central Sumatran 

 conifer, the sporangia are on the "upper'' sur- 

 face. He says that the ovules also are on the up- 

 per face of the sporophyll, and he regards both 

 male and female sporophylls as homologous with 

 those of Lycopodiales. 



The dominant number of sporangia is two, 

 but many conifers have more (fig. 287). The fig- 

 ure shows several genera with two sporangia, and 

 several with more. The number is 2 in all of 

 Abietaceae; 2-5 in the Taxodiaceae; 2-6 in the 

 Cupressaceae ; and many more in the Araucaria- 

 ceae. Araucaria cunninghamia has 13 and they 

 are very large. Agathis australis, the New Zealand 

 Kauri, has 5-15 sporangia on a sporophyll; and 

 in A. hornensis the number of sporangia often 

 reaches 15. Some of the Araucarian sporangia 

 reach a length of 7 mm., and a length of 4-6 mm. 

 is not at all rare. 



In Taxus the sporophylls, each bearing, usual- 

 ly, 6 sporangia, but sometimes as many as 8, are 

 peltate, with the sporangia hanging down, as in Equisctum (fig. 288). 

 In Torrcya the condition is similar, but there arc only four sporangia 

 borne on one half of the nearly peltate top. Coulter and Land's^ 

 found, in the sterile half of the top, resin canals which might rep- 

 resent the missing sporangia. In early stages the resin canals look 

 very much like young sporangia. 



Fig. 285. — Podo- 

 carpus with three 

 male cones. 



