i7 

 NATIVE IRIS NOTES— I 



I. On the Relative Vitality of Louisiana Iris 



In one of the temporary plantations of Gulf State irises at the 

 Botanical Garden, differences in the vitality of various specimens 

 were very evident during the past season. 



An opportunity was afforded to observe the relative growth of 

 the plants over a period of two years in a temporary nursery where 

 the plants were set out in rows as they were received from the field 

 in the spring of 193 1. The rootstocks were planted in rows, so 

 many of each accession number being preceded by a record label. 

 The nursery rows were separated by foot-paths and there was con- 

 siderable walking between the rows of plants. The plants grew 

 vigorously. The majority, moreover, remained within their in- 

 tended bounds. However, notwithstanding the tramping in the 

 paths, the plants of several species grew with such vigor that the 

 rootstocks not only mingled densely in their own allotted space, but 

 grew across the paths on either side and mingled so intimately with 

 those of their neighbors that it was in many cases impossible to 

 separate the two with confidence. The worst "sinners" so to speak 

 were: Iris vinicolor, I. oenantha, I. fourchiana, and some varieties 

 of Iris giganticaerulea. 



II. Autumn Flowering of Louisiana Iris 



Some recent performances among the Louisiana irises may give 

 heart to those who are seeking for a race of autumn-flowering 

 irises. In one of our plantations of irises set out with plants from 

 the temporary nursery referred to above, in the summer of 1932, 

 an interesting phenomenon was observed. About a month after 

 the regular flowering season — June — the plants of several numbers 

 of the irises collected prior to 1931 began to flower. From the 

 first week in August to the last week in September, normal flower- 

 stalks two and a half to three and a half feet tall appeared. With 

 one exception they were pink- or red-flowered species. Some of 

 the stalks bore as many as nine flowers, and many of the flowers 

 were exceptionally fine. Will these plants repeat this routine next 

 year? Unfortunately the late-flowering period did not permit of 

 the ripening of the seeds. The plants under the following Garden 

 accession numbers flowered in the two autumn months : Numbers 



