1840.] Linnean Society. 63 



within the natural order Burmanniacecs, dividing it into two sub- 

 families, \\z. 1. Burmanniea, which will contain only the single 

 genus Burmannia (and perhaps the Gonyanthes of Blume may be 

 found to belong also to this section) ; 2. Dictyostegece, com- 

 prising Dictyostega, Cymbocarpa, Stemoptera, Apteria, Gonyanthes, 

 and Gymnosiphon. He then proceeds to show the close affinity which 

 Burmanniacea bear to OrchidecB, which often also present nearly a 

 naked stem, with imperfectly developed leaves, and instances are 

 moreover known in which they exhibit three distinct stamens and 

 three stigmata : they have also an unilocular ovarium, with parietal 

 placentation ; there exists also a close resemblance in the structure 

 of the walls of the capsule, and there is hardly any difference in the 

 shape and structure of the seeds of Dictyostega and some species of 

 Pleurothallis, which have both a transparent reticulated testa, show- 

 ing distinctly the included nucleus suspended from the apex. The 

 pollen of these plants also bears much resemblance to that of Or- 

 chideee, in being inclosed in a peculiar anther-case, and consisting of 

 coarse grains cohering in waxy masses. Dictyostega orobanchioides 

 also offers a beautiful illustration of the emission of poUen tubes, 

 which are seen penetrating the stigmata in crowded bundles of cot- 

 tony filaments, each thread being clavately terminated by its re- 

 spective grain of pollen. 



There was also read a paper, entitled, " On the existence of Spiral 

 Cells in the Seeds of Acanthaceee." By Mr. Richard Kippist. Com- 

 municated by Prof. Don, Libr. L.S. 



After briefly enumerating the other natural families in whose seeds 

 spiral cells had been previously observed, the author proceeds to de- 

 scribe those of a plant brought from Upper Egypt by Mr. Holroyd 

 (^Acanthodium spicatum, Dehle), whose peculiar appearance when 

 placed under the microscope, first led him to examine those of other 

 Acanthacete, in which family the existence of spiral cells had not be- 

 fore been noticed. The entire surface of the seed in Acanfhodium is 

 covered with whitish hairs, which are appressed, and adhere closely 

 to it in the dry state, being apparently glued together at their ex- 

 tremities. On being placed in water, these hairs are set free, and 

 spread out on all sides, they are then seen to be clusters of from five 

 to twenty spiral cells, which adhere firmly together in their lower 

 portions wliile their upper parts are free, separating from the cluster 

 at different heights, and expanding in all directions like plumes, 

 forming a very beautiful microscopic object. The free portions of the 



