﻿PLATE XVIII. 



Ptilota dentata Okam. 



CERAMIACE/E. 



Nom. Jap, ！ Bcni-liiba. 



Ptilota dentata Okam. Sp. Nov. in Bot. Mag. Tokyo, Vol. VI. ， no. 

 62, 1892， p. 149—150， PI. IV; G. K. de Toni Phyc. Jap. Nov., p. 34 ； 

 Okam. Alp". Jap. Exsic, Fasc. 丄， no. 26. 



Diapii. : Frond compressed, two-edged, mia ribbed, decom- 

 posito-pinnate ； branches distichous, alternate, patent, and also 

 proliferous from the axils of pinnae ； pinnae of simple character 

 regularly alternate, deltoido-acuminate, entire ； those of compound, 

 suppressed in sterile frond, presenting only in fertile frond as a 

 very short fertile pinnae. Fruits of both kinds developed from 

 pinnae of compound character, which are shortened and produced 

 single or seriated along the margin of branches above the axils of 

 simple pinnae. Cystocarps shortly pedicelled, involucrate. Tetra- 

 sporangia collected in a dense globular aggregation on apices of 

 the short pinnae, produced from the terminal cells of pinnulse 

 and of opposite pinnell^e, which are mixed with sterile — simple 

 or pinnated and subclavate ― pinnulse. Antheridia unknown to me. 



Hah. On rocks, stones, shells, calcareous alra etc. near 

 low tide. Rather common along our warmer Pacific coast : Iwaki, 

 Hitachi, Kadzusa, Boshu, Totomi. Cystocarps and tetrasporangia 



— August. 



<_> 



Description •• The root is a small disc. The frond is 

 caespitose, ancipito-compressed, 5-25 cm. high, 2-^5 mm. broad, 



