82 ENGLISH BOTANY. 



local, but spreading over the country, being first noticed by Mr. John 

 New, at " Waringstown, co. Down, about the year 1836," The female 

 plant alone is known to occur in Britain, 



(England), (Scotland), (Ireland). Perennial, Summer, Autumn. 



Plant wholly submerged, the branches rising to the top at the time 

 of flowering, the flowers resting on the water but not rising out of it. 

 Stem slender, cylindrical, brittle, much branched, emitting roots at 

 the nodes. AVhorls rather distant below, approximate towards the 

 apex of the branches, mostly with 3 leaves on each, but sometimes 

 with 4, the lowest nodes with the leaves sometimes opposite. Leaves 

 slightly amplexicaul, ^ to -^ inch long, variable in breadth, bright 

 green, translucent, with a thickened midrib, finely serrulate on the 

 margins, Spathe axillary, from one or more of the whorls to- 

 wards the extremity of the branches, clavate-cylindrical, split at thf. 

 apex, membranous. Tube of the perianth 2 to 8 inches long, filiform. 

 Flowers about } inch across, pale lilac. Sepals concave. Petals at 

 length reflexed, Filamonts strapshaped, without anthers. Stigmas 

 papillose. The male plant or the fruit I have never seen, and even in 

 America it appears to be much less common than the female, which 

 there has the flowers with the stamens apparently perfect. 



Dr. Asa Gray says that the male flowers break otF and float on the 

 surface, as in A^allisneria. 



When groAvn in an aquarium I have seen it with leaves as narrow 

 as those of Callitriche autumnalis. 



Water-Thyme. 



The ListoTy of tliis curious water plant is very interesting, and has given rise to 

 much discussion among botanists as to its introduction into this country. It is the 

 Anacharis Ahinastnnn of the first and subsequent editions of Babington's " Manual of 

 British Botany." More recently it has been identified with a well-known North Ameri- 

 can plant, and referred to the genus Elodia, by Mr. Bentham and others. We are in- 

 debted to Mr. W. Marshall, of Ely, for a very careful collection of facts bearing on the 

 discovery of this plant, and its claim to be considered a British native, in four letters 

 published originally in the " Cambridge Independent Press," and afterwards in the 

 " Phytologist " of 1852. These letters were also published in a separate form, and 

 through Mr. Marshall's kindness we are able to avail ourselves of them fully. 

 This weed was first found in this country on the Srd of August 1842, by Dr. 

 George Johnston, of Berwick-on-Tweed, in the Lake of Dunse Castle, in Berwick- 

 shire. Specimens were sent to Mr. Babington, but the discovery was lost sight 

 of, and the interest died away until the autumn of 1847, when it was again disco- 

 vered by a lady, Miss Karby, of Market Harborough in Leicestershire. The plants 

 were all females, and were closely matted together in great abundance. Miss Kirby 

 had not observed it there before, and the reservoirs had been cleaned out two 

 years previously. Miss Kjrby's rediscovery awakened the attention of botanists to 

 the subject, and Mn Babington published a description of the plant in the " Annals 

 of Natural History" for February 1848, in which he advocates the notion that 

 Udora is a true native, and not, as is since pretty generally believed, an introduc- 



