489 



to consist of fascicles of long, cylindrical, transparent tubes, firmly cohering for about 

 one third of their length, and presenting all the characters of spiral vessels. These 

 fascicles usually contain from five to twenty tubes ; each tube inclosing one, two, or 

 occasionally even three, spiral fibres, which adhere closely to the membrane. The fi- 

 bre may be sometimes seen to divide into two in the upper part of a tube, the branches 

 usually continuing distinct ; sometimes, however, after making a few turns, they again 

 coalesce. Towards the free extremity of the tube the fibre is frequently broken up in- 

 to a number of distinct rings; and in other cases the spire again becomes continuous, 

 after having been interrupted by two or three such rings. In those portions of the 

 tubes which adhere together, the fibre is completely reticulated ; towards tlie extremi- 

 ty, the coils, though quite contiguous, are usually distinct, and readily separate by the 

 expansion of the tube ; in the intermediate parts they adhere more firmly together, be- 

 ing connected by slender ramifications of the main fibre. The expansion of the hairs 

 in water is accompanied by a copious discharge of mucilage, which makes its escape 

 by distending and finally rupturing laterally the spiral tubes in which it is contained. 

 " The testa, which is distinctly visible in the spaces between the hairs, consists of 

 nearly regular hexagonal cells, each containing an opake mass of grumous matter, 

 which, not filling the entire cavity, leaves a wide transparent border. Cells similar to 

 these, but more elongated and gradually passing into the form of tubes, immediately 

 surround the base of each hair, which appears to be filled up by a conical mass formed 

 of the transparent tubular portions." — p. (55. 



Mr. Kippist was induced, by the peculiar appearance of these seeds, 

 to examine those of other genera of the same natural family, with the 

 view of ascertaining to what extent the tendency to develope spiral 

 hairs might prevail, and whether that peculiarity might assist in cha- 

 racterizing genera. He finds that the presence of these cells is not 

 universal in the Acanthaceae, but has met with many examples, with 

 "a considerable diversity in the structure and arrangement of the hairs 

 which clothe the seeds." He describes the hairs of the seeds of a 

 great number of species of Acanthaceaj, which appear to vary greatly 

 in form and structure. We regret that our limits prevent us from se- 

 lecting examples. The beautiful illustrations are from the author's 

 own drawings. 



X. Description of a new genus of Plants from Brazil. By J .Mieks, Esq. F.L.S 



Read March 2, 1841. 

 This is a minute dioecious plant found by Mr. Miers in the Organ 

 mountains, Brazil, in February, 1838. Its texture is quite transpa- 

 rent, and the structure of its flowers very singular. Its position in the 

 system is not accurately determined, but the author is disposed to 

 place it near the Juncagineae ; in habit it resembles some Orchideae. 

 It is named by the author Triuris hyalina — the generic name referring 

 to the three elongated processes of the perianth. The illustrations 

 are from the pencil of the author. 



