CYATHEOIDES. 



627 



4. Longitude section of sorus, 



5. Vertical views of sorus with portion of pinnule, the 

 hairs spread out. 



6. Hairs of receptacle. 



7. Theca. 



This has the habit of Cyathea. The sori occupy the tertia- 

 ry veins, and are never found on the fork of the central 

 one. 



The receptacle is much developed, the theca subsessile and 

 immersed in the hairs which are of very irregular form, and 

 not unfrequently cohere. With Trichopteris it agrees in habit, 

 but the venation is different, and that genus has no recepta- 

 cle, it agrees also with it in the subsessile theca, and in the 

 form of this organ. Whence my specimen came I am un- 

 aware. 



It agrees almost entirely with an Alsophila, I have from 

 Gubroo Purbut, (Assam.) in which the indusium is reduced 

 to a series of hairs, and these are likewise produced from the 

 receptacle. The principal distinguishing mark of Alsophila, 

 is the situation of the sorus. 



Did the hairs only originate from the base of the receptacle^ 

 the plant would be nothing more than a Cyathea, but as 

 they originate from the whole of its surface, it is distinct. 



It will perhaps hence appear, that the receptacle of Cyathinse, 

 is the most permanent character, as might be expected from 

 Woodsia, and those species of Alsophila in which the indusi- 

 um is obsolete. 



In Cyathea longifolia, as Brown has pointed out, the sori are 

 on the lateral veins. In C. venulosa, which has a similar habit, 

 the pinnulse being entire, the sori have a similar distribution, 

 but occasionally occupy a furcature. The habit of these are so 

 distinct from the true Cyatheae, that there is no doubt of their 

 forming a distinct genus. They agree in habit with the pre- 

 sent subject. Cyathea sinuata Hook, et Grev. vol. 1 t. 106 will 

 belong to the same as C. longifolia, and C. venulosa, if its 

 simple frond is not sufficient to distinguish it. 



