Linnaan Society. 461 



in a spiral manner, except in the terminal cells, where it is more 

 abundant and gives them a darker colour. This stage Mr. Thwaites 

 regards as analogous to the confervoid filaments which form the pri- 

 mordia of a moss, or to the mycelium of a fungus ; and he adds that 

 Kiitzing has described and figured the early condition of Lemanea 

 torulosa, Agardh, as very similar. 



From a cell near the base of this conferva-like structure a branch is 

 given off, which at first differs apparently from the ordinary branches 

 only in its cells being much shorter. This little branch increases 

 rapidly in length and thickness from the multiplication of its cells 

 by fissiparous division ; and to enable it to acquire a firmer support, 

 a number of roots are given off from its base (in the same manner 

 as in the phyton of a moss), and it is thus enabled to attach itself 

 and maintain an independent existence. From this period it gra- 

 dually puts on the well-known characters of the full-grown Le- 

 manea. 



Mr. Thwaites believes that the study of the early development of 

 the Algce would well repay the careful observer. He thinks it highly 

 probable that very many of the structures now classed with the Pal- 

 mell(B are merely immature states of more complicated species ; but 

 he recommends great caution in such investigations, as without a 

 good microscope and a practised eye, very essential characters readily- 

 escape detection. 



Read also a portion of Dr. Buchanan Hamilton's Commentary on 

 the 9th Part of Van Rheede's Hortus Malabaricus. 



March 7. — The Lord Bishop of Norwich, President, in the Chair. 



Read a memoir " On Melianthece^ a new natural order of plants, 

 proposed and defined by J. E. Planchon, docteur-^s-sciences." Com- 

 municated by the Secretary. 



After an introductory critical sketch, the author proceeds to com- 

 pare together Melianthus, Diplerisma (a new genus founded upon 

 Melianthus minor, L., and Mel. comosus, Vahl), Natalia and Ber- 

 sama; that is to say, the four genera which he proposes to unite 

 under the common name of Melianthece. This comparison includes 

 chiefly descriptive details, of the results of which the following 

 synoptical table will afford a summary view : — (^See the Table on 

 pp. 462-3.) 



A glance at the characters suffices to show that those among 

 them which are common to all the genera are also of undoubted 

 primary importance in most natural tribes. So, for instance, the 

 structure of the seeds, the relative position and numerical propor- 

 tion of the floral parts, the position and even the shape of the disc, 

 the pinnate leaves and the constant presence of stipules, are so many 

 points by which the connection of these plants is established. Ad- 

 mitting then the homogeneity of the order, the author proceeds to 

 point out its more general affinities. 



