lxii Obituary Notices of Fellows deceased. 



and his enthusiasm for research enabled him to compress into a short 

 scientific career more useful work than most botanists would have been able 

 to accomplish. 



Most of the papers published during his official connection with the Eoyal 

 Gardens deal with systematic botany ; he contributed accounts of several 

 new species to the ' Icones Plantarum,' and in collaboration with Mr. Botting 

 Hemsley, described collections of plants made by Dr. Sven Hedin and 

 Sir Martin Conway from Central Asia and the Bolivian Andes respectively. 

 He assisted Mr. Hemsley in his comprehensive account of the flora of Tibet. 

 He wrote an article on the flora of Palestine for the 'Encyclopaedia Biblica,' 

 contributed a section on the Verbenaceae to the ' Flora Capensis,' and one 

 on the Thymelseaceae to the ' Flora of Tropical Africa.' At the suggestion of 

 Sir William Thiselton-Dyer, he investigated the morphology and functions 

 of the double pitchers of four species of Dischidia. He showed that the 

 outer pitcher is part of a modified leaf and corresponds morphologically 

 to the single pitcher of Dischidia Bajflesiana, the inner pitcher being formed 

 from the inflexed apical lobe of the leaf. Good evidence is brought forward 

 in favour of the view that the soil in the pitchers is carried there by 

 ants, and that they use the inner pitchers as a refuge during temporary 

 floodings of the larger outer pitchers. This piece of work is surprisingly 

 good considering that the material examined consisted of herbarium 

 specimens. 



The most important contributions made by Pearson to Morphological 

 Botany are those on the Gnetales. His first visit to the Welwitschia 

 country was in January, 1904, but the Herero rebellion seriously interfered 

 with his field observations. In a paper published in 1906 in the 

 ' Philosophical Transactions,' he describes the climatic and physical 

 conditions of the German territory, where he received invaluable help 

 from the Imperial Consul-General, and gives an interesting account of his 

 observations on the habit and habitat of "Welwitschia. He expresses the 

 opinion that the period, 70-100 years, usually assigned as the duration of 

 life, is much too short, and confirms Marloth's statement that Welwitschia 

 is dioecious ; he considers that the cones are probably pollinated by insects, 

 and records the frequent occurrence of the beetle, Odontopus sexpunctulatus, 

 though it was not until a subsequent visit that ,he obtained evidence 

 convincing him that Odontopus is the pollinating agent. Much new informa- 

 tion is given as to the development of the male and female flowers. 

 Hooker's account of the ovule is generally confirmed and considerably 

 extended. In the earlier stages of development the embryo-sac contains 

 numerous free nuclei ; this condition is followed by partial septation, which 

 produces a tissue of multinucleate compartments. He found that, in the 

 upper part of the embryo-sac, each " cell " has 1-2 nuclei, and later as many 

 as 5, while in the lower part of the sac each " cell" has 2-12 nuclei. The 

 " cells " with 2-5 nuclei produce prothallus-tubes which, he shows, contrary 

 to Strasburger's view, cannot be regarded as equivalent to archegonia. He 



