BEACTLETS SUBTENDING INNER NECTARIES. 33 



tiuii of the keleps for a longer period. The temporary character of 

 the secretion in our United States sorts was reported by Professor 

 Trelease several years ago. 



In Guatemala, however, the young bolls seem to l)e quite as effi- 

 cient as the flowers. It is even possible that this generosity on the 

 part of the plant is excessive, since if the number of keleps is small 

 they may find all the nectar they need on the lower bolls, and hence 

 have less inducement to inspect other parts of the plant. Under 

 favorable conditions in Texas the cotton plant produces a much 

 larger number of flowers than in Guatemala, so that what is lacking 

 in quantity may be made up by numbers, in case it should become 

 possible to utilize the keleps in Texas. 



RACTLETS SUBTENDING INNER NECTARIES. 



The Kekchi cotton is distinguished from all our Upland and Sea 

 Island types by the more regular presence and much larger size of 

 a series of bractlets, a pair of which usually subtends each of the 

 inner nectaries. In other varieties these are either wanting entirely 

 or are rare and rudimentary." The bractlets are inserted somewhat 

 obliquely, with their margins in contact below the nectary. 



Sometimes they serve to conduct nectar to the edge of the involucral 

 bracts, the nectar following along between the slender bractlets like 

 ink between the nibs of a pen, as though to coax the keleps inside the 

 involucre. This must happen rather infrequently, however, to judge 

 from the great irregularity in the size of the bractlets. Sometimes 

 they are half an inch or more long, and extend well into the angles of 

 the involucre, or even project outside. (PI. III.) Nevertheless, it 



o Professor Trelease, who studied the American Upland varieties, appears not 

 to have found the Ijractlets in pairs. He says: "These glands (the inner nec- 

 taries) belong in reality to an inner whorl of three jiracts. alternating with 

 the outer ones, but generally wanting. In stunted plants, especially as cold 

 weather conies on. one or more of these inner bracts may be found." (See 

 Comstock, 1875, Report upon Cotton Insects. .'',24.) 



The shape and position of the bractlets seem to warrant the suggestion tliat 

 they represent the stipules of the outer bracts instead of an independent inner 

 whorl of bract leaves which lias first become specialized and then become rudi- 

 mentary. The suggestion has the further warrant in that it may help to explain 

 the numerous involucral appendages of some of the related plants, which range 

 about the number 9 — that is, 3 leaves and 6 stipules. The normal number should 

 be 6. if the two whorls of leaves were represented. One of the Guatemalan 

 species of Hibiscus examined with this interpretation in mind seemed to con- 

 firm it by showing very often 3 of the appendages broader than the others, 

 though the total number varied from 8 to 11. with an irregularity quite compar- 

 able to that of the bractlets of the cotton. Even the bracts of the cotton some- 

 times vary, involucres of 2 bracts being found occasionally, and in rare 

 instances 4. 



9962— No. 88—05 Ai 3 



