Botanical Society of Edinburgh, 503 



The following papers were read : — 



1. "Experiments on the Dyeing properties of the Lichens,'* by 

 W. Lauder Lindsay, M.D., Assistant Physician Royal Crichton 

 Institution, Dumfries. 



The author presented to the Society the tabulated results of between 

 500 and 600 experiments made two or three years ago, the chief object 

 of which was to endeavour to call attention to the fact, that we pos- 

 sess in our own island Lichens capable of furnishing dyes nearly, if 

 not quite, equal in beauty to Orchil, Cudbear, and Litmus. 



2. ** On a species of Potamogeton from Lough Corrib," by Mr. 

 J. Kirk, of Corentry. Mr. Kirk considered the Potamogeton as 

 allied to the P. longifolius of * English Botany Supplement,' and. 

 remarked : — 



** My specimens differ from the plate in Eng. Bot. Sup. in having 

 most of the leaves on long stalks, and in the absence of the apiculus. 

 The specimen there figured was picked up floating [growing from the 

 bottom, not loose — Ed. Ann. Nat. Hist.] in Lough Corrib in July 

 1835, by Mr. J. Ball, * whilst sailing between Ma'am and Cong,' and 

 given by him to Mr. Babington, and is the only specimen known to 

 have been found in the British Islands up to September 1853. The 

 most striking character in my specimen is the singular and prominent 

 midrib, the central portion of which consists of three longitudinal 

 veins or ribs running closely parallel with each other, whilst on either 

 side are three to six ribs running closely parallel to them, but rather 

 more distant from each other ; the whole connected by transverse 

 veins, and in the fresh state often more than one-fourth of an inch 

 in width, appearing, until closely inspected, a compact solid midrib, 

 on either side of which are two to five fine veins, the whole con- 

 nected by numerous secondary veinlets. Some of the submerged 

 leaves were 18 inches in length, and most beautifully pellucid, in 

 this respect far surpassing the other British members of the genus. 

 The floating leaves were scarcely coriaceous, linear-lanceolate or lan- 

 ceolate, and occurred only in small quantities. The original specimen, 

 in Mr. Babington' s possession, exhibits traces of this peculiar midrib, 

 which, I think, is almost sufficient to identify it with my specimen. 

 The differences alluded to in the outset are not more than may be found 

 between specimens of well-known species gathered in their prime, 

 and others gathered, as in the present specimens, where decay has 

 actually commenced — witness P. rufescens and P. zostercef alius. In 

 the last-named species, the early leaves are invariably apiculate, but 

 no trace of an apiculus is to be found in those produced during or 

 after flowering-time. Whether the plant is identical with P. longi- 

 folius (Gay), is a question I am not prepared to answer, but feel 

 much disposed to doubt the latter being anything more than a name ; 

 at any rate no individual with fresh specimens of my Lough Corrib 

 plant before him could overlook the prominent midrib (although in 

 the dried state it is not nearly so conspicuous) . Mr. Babington, from 

 inspection of some of my dried specimens, considers it different from 

 his original specimen on the grounds already stated, and is disposed 

 to look upon it as perhaps the Potamogeton sparganifoUus of Fries. 



