(94) 



perhaps, by accident ; the surface smooth and somewhat polished when 

 young, more or less rough when old. Structure loosely reticulated, 

 with large quadi'ate cells. Substance membranous, more or less coria- 

 ceous when old, and then not adhering to paper. Colour, a rather 

 dark greenish olive, becoming of a rusty brown or a dark umber brown 

 when old. Fructification consisting of roundish ovate, very minute 

 spores, collected into little roundish oblong groups or sori, mixed with 

 short, ovate, jointed filaments, and scattered abundantly over the whole 

 sm-face of the frond. 



When clean and well grown, this is a very pretty species, but by the 

 time it is full-grown it very often becomes more or less the prey of 

 other parasitical species, and is torn or abraded in the upper part, so 

 that the original elliptic-lanceolate form is lost. 



In this battered form it often sm'vives till the next summer, when its 

 surface and edges become quite shaggy with parasites, and its reticula- 

 tions become so filled up with their radicles, that its structure becomes 

 almost obliterated. 



In its habit it is not only tufted but csespitose, often forming exten- 

 sive patches either along the shallow margins of the pools or on isolated 

 stones, which it frequently envelopes with a shaggy covering which 

 hangs gracefully down on all sides, very much in the manner of Ulva 

 linza, and gracefully waving backwards and forwards with each retreat- 

 ing or returning wave. 



At first the colour is a rather pleasant olive green without much gloss, 

 but the older parts soon become tinged with brown, and this colour 

 gradually spreads upwards until the whole frond is of an ochry brown 

 colour, and very little of the original olive tint remains. 



From the last species it may be distinguished by the narrow elliptical 

 outline, lai'ger reticulations, brown colour, and rather thicker substance, 

 and the narrow states from Laminaria fascia by the reticulated structure, 

 dull sm-face without gloss, and brown colour. 



EXPLANATION OF PLATE CLXIV. 



Fig. 1. — Punctaria plantaginea, natural size. 

 2. — Surface of frond witli sorus. 

 3. — Same witli antheridia ? 

 4. — Transverse section of frond. 

 5. — Sorus. 



6. -Spores from same. 

 7. — Antheridia ? All magnified. 



