42 DESCRIPTIONS OF N.Z. FERNS. 



envelop the sorus while young, and look like a ball : afterwards opening above, so as 

 to expose the ripe capsules, and allow the spores to escape as the capsules burst. 

 Generally arborescent. 



GENUS CYATHEA. (Si-a-the-a.) 



Sori on a vein, or in forking of a vein. Receptacles elevated, globose, or 

 elongated. Involucre inferior {i.e.j beneath the sorus) globose at first, afterwards 

 bursting at the top, and opening into a cup (whence the name) with an even or 

 irregular margin. Fronds simple, pinnate, or decompoundly pinnate. Arborescent. 

 We have three generally recognised species of this genus in the colony, viz. — ^C. 

 medullaris, C. Cunninghamii, and C. dealbata, and another, C. Milnei in the 

 Kermadec islands ; but as I shall show, some authorities consider that more ought to 

 be reckoned ; as they regard the varieties of form, etc., as sufficient to justify 

 separation into distinct species. 



CYATHEA MEDULLARIS. (Si-a-the-a me-dul-la-ris.) 



"BLACK TREE FERN." " MAMAKU " OR " PITAU " OF THE MAORIS. 

 PLATE IX., Ko. 3; and PLATE XXIX., No 1. 

 This is the largest of our tree ferns, often attaining a height of sixty feet and 

 occasionally far more. It also occurs in Victoria. The caudex is rather slender- 

 looking in proportion to the plant, particularly in tall examples. These however have 

 generally a large conical base of hard, matted or felted, root-fibres, which is sometimes 

 three feet or more in diameter at the surface of the ground. The Maoris split this 

 fibrous cone into slabs two or three inches thick, which they use for lining their potato 

 pits, and for walls of their whare-punis, as rats have a dislike to gnawing through it. 

 The fern may be at once distinguished from all the other tree-ferns by the caudex 

 being covered with flattened or slightly hollowed scars, where the bases of old fronds 

 have broken clean off, and by its black colour. It is also generally more or less covered 

 with black scales or hairs between the scars. In tall plants, the old fronds break off 

 almost as soon as they wither, but in smaller ones, say ten feet to twenty feet high, in 

 sheltered situations, they often hang round the caudex for several years, before they 

 become detached ; in fact, they then appear to be gradually pushed off by the growth 

 of the aerial root-fibres, which, however, are few in number considering the size of the 

 fern. The fronds vary greatly in size, being not more than six feet long in tall plants, 

 while in smaller ones they often attain a length of fifteen feet to twenty feet. This 

 does not appear to depend on shelter, as one often sees plants with these large fronds 

 in open situations, or on lawns in gardens, for which culture this plant seems the best 

 suited of any of the N.Z. tree ferns. The stipites are longer, in proportion to the fronds, 

 than those of the other tree-ferns, being longest in young plants. They are black on 



