﻿VIRESCENCE OF OXALIS STRICTA. 



BY HENRI HUS. 



Specimens of Oxalis stricta* with bright green petals were 

 for the first time observed in the early part of September, 

 1906, in the immediate vicinity of St. Louis, in an unused 

 portion of Bellefontaine Cemetery, not far from Florissant 

 Avenue, which skirts its southeastern boundary. For the 

 sake of convenience these plants are designated as Oxalis 

 stricta viridiflora. Their discovery was entirely accidental, 

 for the plants were few in number, certainly not more than 

 twelve. Interspersed with normal plants of Oxalis stricta 

 and grasses, they formed a patch not larger than eight square 

 feet. The spot was revisited several times during the fall 

 of the same year and during 1907. Specimens gathered on 

 these trips as well as plants raised this year from seed collected 

 last fall, yielded the material on which this paper is based. 



With the exception of the petals and perhaps of the fruit, 

 the plant agrees in all respects with the published descriptions 

 of Oxalis stricta L. The plants are equally vigorous, but 

 both flowers and fruit are smaller. The average length of 

 100 nearly ripe fruits of 0. stricta collected in the vicinity of 

 St. Louis, was found to be 17 mm. ; the average length of 100 

 petals of the species collected in the same neighborhood and 

 in spring was 8 mm., of the same number, from the same 

 locality but collected in fall 6 mm. The same measurements 

 made on parts of Oxalis stricta viridiflora, yielded respectively 

 12, 6 and 5 mm. 



A microscopical examination of petals and sepals of the 

 species and its variety overthrew a preconceived notion as to 

 their minute structure, an opinion based on studies of Epi- 

 lohium hirsutum cruciatum, Oenothera Lamarckiana cruciata 

 and others. t It was expected that since the petals had 



* This is Oxalis stricta as represented in the Linnaean Herbarium, 

 according to Small (Bull. Torr. Club. 28 : 2G7) and Robinson (Jour. Bot. 

 44 : 386), though not of most English and American writers. It is the 

 0. corniculata Dillenii of Trelease in Syn. Fl. N. Am. 1' : 3G5. 

 I De Vries, Hugo. Die Mutationstheorie. 2 : 593. 



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