12 



tbe exclusion of other lierbaceous vegetation.) Species of hydropbile 

 habit, on the other hand, are often gregarious or even social. G. cana- 

 (lensifi, for example, occasionally grows in nearly pure formations, cover- 

 ing open swamps and meadows with an almost unmixed growth. 



TERATOLOGY. 



Abnormal variation of different organs is not infrequent in CaJama- 

 (iro.stis, especially in specimens growing at high altitudes and latitudes. 

 Proliferation of the spikelets, the presence of a second (staminate) 

 Hower or even a third in the spikelets, and increase in the number of 

 nerves in the glumes, are the most common deviations from normal 

 characters. Such deviations are sometimes, but by no means always, 

 due to disease. The following abnormalities in various organs were 

 noted in the material examined in the preparation of this paper: 



1. Three well-developed leafy branches from oue of tbe culm nodes (C. canadensis 

 acuminata). 



2. Rudimentary sheath (?) at first node of rachis of panicle extended into a several- 

 nerved bract aliont 5 mm. long, having the appearance and texture of a ligule (C. 

 langsdorffn): into a bract about 4 mm. long, flat, ovate, 3-uerved (C. canadensis): 

 into a bract 3 mm. long, somewhat spreading, sulbulate, chartaceous, possibly repre- 

 senting a blade (C. macoiiniana). 



3. Panicle deeply lobed, with the appearance of a cluster of panicles {C.nei/Iecta 

 horealis). 



4. Most of the spikelets 2-flowered, oue 3-flowered. In the latter case the first 

 flowering glume subtending an undevelopeil caryopsis, the second a mature cary- 

 opsis, and the third empty, the rachilla being villous between the glumes and 

 extending beyond the uppermost one {C.aJeutica). Many of the spikelets in some 

 panicles 2-flowered, the second flower staminate, Avith well-developed but some- 

 what smaller anthers, the rachilla bearded between the two flowering glumes and 

 with the usual bearded prolongation (Csithflexnosa). A number of spikelets in oue 

 panicle 2-flowered, the second flower staminate, with a smaller but well-developed 

 flowering glume and palea (C.hrevisefa). A second (staminate) flower with well- 

 developi d anthers, the rachilla villous between the llowering glumes and with the 

 usual villous prolongation (C.^xfrj^xmsceHs). In one (diseased) panicle each spikelet 

 witli a second (5-nerved) flowering glume .slightly raised above the first (7-nerveil), 

 both glumes having dorsal awns of about equal length and neither having palea'. the 

 rachilla not extended beyond tlie second (C.pnrpnrascenx). A second* (staminate) 

 flower with well-developed anthers subtended by a narrow, short-awned glume 

 {C.ciisickii). A second flowering glnme. beariug a long, nearly a]iieal awn (C. 

 howeUii). A slender awn, equaling the flowering glume, borne at the summit of the 

 prolongation of the rachilla (C. holanderi). 



o. First empty glume sometimes with a faint lateral nerve (C.pu7-purascens, etc.). 

 In an abnormal, 2-flo\vcre(l spikelet, the first emi)ty glume cleft nearly to the middle, 

 the lobe nearly as wide as the glume itself and with a second (lateral) nerve extend- 

 ing from the base of the glume 1o the apex of the lobe; the second glume cleft to the 

 very base, the halves eacli 3-nerved and each nearly as large as the normal empty 

 glume (C. Huhjlcxnosa). First empty glume freiiueutly 3-nerved and the second 

 4-uerved, the fourth nerve faint and disapi)eariug a short distance above the base 

 (C. aleulica). 



6. Flowering glume in one spikelet 0-nerved, the sixth nerve fainter than the 

 rest and extending into a minute lateral tooth some distance below the a])OX of the 

 glume (('. piirpHvancens) . Teeth of the flowering-glume sometimes 0.5 nun. long(6'. 

 jinrpinaHrenH). 



