JOURNAL OF THE ARNOLD ARBORETUMVOL. XXXIII JULY 1952 NUMBER 3WILLIAM JACK'S GENERA AND SPECIES OF MALAYSIAN PLANTS E. D. MERRILL With one plate THIS PAPER was not planned to consider other than certain phases ofJack's botanical work. Hooker published an excellent biographical sketchof William Jack prefixed to one of the series of papers in which the Jackplant descriptions of 1820-22 were republished, to which the reader isreferred.1 Supplementing these data are the remarkably interesting letterswritten by Jack to Nathaniel Wallich from Penang, Jan. 14 to May 19,1819, from Singapore, June 8 to June 18, 1819, and from Bencoolen,Sumatra, Aug. 19, 1819, to Oct. 26, 1821.2 These letters contain a wealthof information regarding Jack's experiences and observations as a pioneerbotanist operating in the then botanically unknown and very rich forestsof Penang, Singapore, and Sumatra. For Jack was indeed the pioneer post-Linnean Malaysian botanist, his work antedating the investigations ofBlume at Buitenzorg, Java, which were initiated, as to publication, in 1823,a year after Jack's death. On February 12, 1819, he wrote to Wallich. "Iam overwhelmed with the treasures that pour in upon me; I have been em-ployed night and day so as not even to leave time for correspondence. Iactually wish for a little remission, as my cough has been teasing me, buthow is it possible! I cannot even now get through all; my specimens arein piles that are quite alarming and I have not time to look over them. Imust however take a day or two to make a selection for you." An excellentsummary of the essential data regarding William Jack and his botanicalaccomplishments has been included by Mrs. M. J. van Steenis-Krusemanin her recent publication.3 1Hooker, W. J. Description of Malayan Plants. By William Jack. With a briefMemoir of the Author and Extracts from his Correspondence. Comp. Bot. Mag. 1:121-147. 1835. 2Burkill, I. H. William Jack's Letters to Nathaniel Wallich, 1819-1821. Jour. Straits Br. Roy. As. Soc. 73: 148-268. 1916. s Van Steenis-Kruseman, M. J. Malaysian Plant Collectors and Collections,Fl. Malesiana I, 1: 256-257. 1950.