30 Proceedings of the Biological Society of Washington. 



slender branches ascending ; rays and their lower branches very pubescent 

 at the thickened bases ; spikelets dark purple or less commonly pale, un- 

 awned, readily deciduous, the sterile on pedicels more than half the length 

 of the fertile; lower glume membranaceous, elliptic, 4 mm. long, 1.8 mm. 

 wide, 7-nerved, green or straw-colored when mature; upper glume 

 coriaceous, chestnut-colored and shiny when mature; anthers 2 mm. 

 long; caryopsis yellow, obovoid, 1.5 mm. long. 



This subspecies is very different from those above discussed in its much 

 coarser stems and broader leaves, in which respect it more closely re- 

 sembles the cultivated sorghums. The innovations are all extravaginal 

 and mostly short, but stout elongated rootstocks are occasionally formed. 

 The blossoms appear much later than in A. halepensis {genuinus) ; indeed 

 it does not reach bloom at Washington, D. C, at the time it is killed by 

 frost, but the rootstocks survive the winter. At Biloxi, Miss., plants two 

 years old do not bloom until the end of October. 



Originally collected by Haenke in Luzon. Abundant near Manila, 

 whence the seed was received to cultivate the plant. Specimens examined : 

 Davao, Mindanao, Copeland No. 466; Arayat, Luzon, Merrill No. 1468; 

 P. I., Loher No. 7169, 7209; Luzon, Cuming No. 569; Balabac, Vidal 

 No. 3996; Los Banos, Luzon, Elmer No. 8287; Novaliches, Luzon, Loher 

 No. 1806; Montalban, Luzon, Loher No. 1807; Buru, Reidel ; Borneo, 

 Bangamassing, J. Motley No. 444; Borneo, Sarawak, Beccari No. 3924. 

 The specimens from Borneo drop their spikelets very readily. Hainan, 

 Henry No. 8295; North River near Canton, Hance No. 4879; Tai Fu, 

 C. Ford No. 484. These three Chinese specimens are somewhat ambiguous 

 toward siamensis. 



Andropogon halepensis siamensis n. subsp. 



Closely allied to propinquus, differing only in the larger spikelets 4.5 to 

 5 mm. long. 



Cambodia, Pnum Penh, Godefroy-Lebeuf No. 83, Oct. 1878 (Kew); 

 Siam, Pak Bawag, Kerr No. 2006, Sep. 4, 1911 (Kew); Siam, near Kam- 

 pang, Kerr No. 2156, Oct. 11, 1911 (Kew) (type) "12-15 ft. high; 

 growing in pampas along banks of Mei Ping river." 



From propinquus this is easily separated by its much larger spikelets 

 and from muticus by the larger size, broader leaves and larger more 

 densely floriferous panicle. 



Andropogon sorghum (L. ) Brot. 



Holcus sorghum L. Sp. PI. 1047. 1753. Based on descriptions of cultivated 

 sorghums by Bauhin and other writers. From the various synonyms 

 cited by Linnaeus, his conception of the species in 1753 included only 

 varieties with the lemmas awned, but with the glumes glabrous or 

 villous and the grains yellow or white. By tracing the synonyms given 

 by Linnaeus it is seen that his species included not only the sorghum 

 with yellow seed and smooth glumes then as now cultivated in southern 

 Europe and supposed to be from India, but also one, perhaps two, 



