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IX. On the existence of Spiral Cells in the Seeds of Acanthacese. By Mr. 

 Richard Kippist, Libr. L.S. Communicated by the Secretary. 



Read March 17th, 1840. 



J. HE existence of spiral cells in the envelopes of the seed, has, as regards 

 several families, been long known among botanists. They were first disco- 

 vered by Mr. Brown in the pericarps of Casuarinece, and subsequently in the 

 testa of some Orchidece. Lessing detected them in Compositce ; Horkel and 

 Schleiden in Lahiatce, Polemoniacece, and Hydrocharidece ; and Dr. Lindley 

 has published in the 'Botanical Register' a detailed account of their appear- 

 ance in the seeds of Collomia. As, however, I am not aware that any author 

 has yet noticed their occurrence in those of Acanthacece, and as I have been 

 fortunate enough to meet with them in many species of that family, present- 

 ing, as it appears to me, some peculiar characters, and in some cases attain- 

 ing an unusual degree of development, I venture to hope that the following- 

 account of my observatioas may not prove unacceptable to the Linnean So- 

 ciety. 



My attention was first directed to this subject by witnessing the very beau- 

 tiful appearance under the microscope of an Acanthaceous seed, forming part 

 of a collection brought by Mr. Holroyd from Upper Egypt, and presented by 

 him to Professor Don. It is of a lenticular form, covered, especially towards 

 the margin, with whitish hairs, which are closely appressed to the surface, and 

 glued together at their extremities, so as rather to resemble corrugations of 

 the testa than distinct hairs ; on being placed in water, however, they are set 

 at liberty, and, expanding on all sides, are seen 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. 



VOL. XIX. K 



