2 78 BOTANICAL GAZETTE [September 



masses of foliage like great pompons 



along the stems at distant intervals. From these whorls occasion- 

 ally spring slender, divaricate, elongated branches bearing leafy 

 tufts like those of the main culms, but less dense and with shorter 

 blades, the ultimate branches almost capillary and bearing but a 

 single leaf at a node. 



multispicatum occurs on mo 



mountains 





culms 



branches are beset with very short, sharp-pointed retrorse prickles. 



from n to 1 2 feet or more 



whip 



Only after 



some 



from 



branch buds. The prickles later fall off, the old culms being 

 smooth. These long grappling branches are freely produced, 

 resulting in an inextricably tangled mass that draws blood at every 

 foot of one's progress through it. The short leafy branches are 

 rather less densely whorled than in either of the other species, there 



i node. The lanceolate, not crowded, 



from 



blades are 6-8 cm. long and i 



■& 



2 mm 

 5 cm - 



The most beautiful and interesting of the climbing bamboos is 

 Arthrostylidium sarmentosum. This I found on nearly every wet 

 high mountain, having collections from ten stations. It had been 

 collected before in but three stations and was unknown in flower, the 

 original description having been drawn from sterile specimens. 

 Among mountain palms on the forested north slope of El Yunque 

 (ascending from Rio Grande), at about 3000 feet altitude, it was 

 found in abundant bloom December 2, 1913 (Chase no. 6730). 

 This is the only time it has been known to flower. The condi- 

 tions here, so far as could be seen, were in no way different from 

 those under which it grew elsewhere and failed to bloom. Fifty 

 herbarium specimens were prepared and several have since been 



this 



The inflo- 



rescence consists of short-exserted, terminal and axillary, strongly 

 zigzag racemes of 2-5 spikelets, the rachis joints flat on one side, 

 minutely ciliate on the edges, a strong pulvillus at the base of each 

 joint forcing it to bend back at right angles to the joint below. 



