903 



flowers and its woolly stem. Specimens of it have been shown to se- 

 veral eminent botanists, who have expressed very different sentiments 

 respecting it, but most of them have considered it an interesting plant, 

 and a form which they had never before seen. One is of opinion that 

 it is an instance of Carduus arvensis being dioecious, this plant hav- 

 ing the stamens more largely developed, which might account for the 

 difference in the length of the pappus. Another considers that it has 

 nothing to do with C. arvensis, but is C. acaulis, B. duhius of Willde- 

 now's ' Species Plantarum,' and C. caulescens of Persoon. A third 

 would give it the name of acaulis, had not the stems been of such a 

 height, although he thinks the leaves more like arvensis. A fourth is 

 ready to suppose, that it must be a hybrid between C. acaulis and ar- 

 vensis, the flowers and hairiness of the stem bringing it exactly to the 

 former, and the leaves and size agreeing mth the latter. Several 

 others have expressed opinions similar to one or other of those given 

 above: and when such a difference exists among the most competent 

 judges, I feel unwilling to hazard a sentiment, but the first explana- 

 tion does not appear by any means to account for the whole of the 

 very striking differences between this plant and C. arvensis ; with the 

 second 1 do not feel able to unite, because although C. acaulis has 

 been frequently found caulescent in this neighbourhood, and I have a 

 specimen of it gathered last autumn, with a stem thirteen inches in 

 height, yet it always preserves, as far as T have seen, its general dis- 

 tinctive characters, and presents a very different appearance to the 

 plant under consideration. I fear that there are not sufficient dis- 

 tinctive peculiarities to constitute it a separate species, and therefore 

 the only other alternative seems to be to consider it a hybrid between 

 C. arvensis and acaulis, which, though an uncommon occurrence in 

 nature, is by no means an impossible one. Perhaps some of your 

 correspondents may have seen a similar plant, and be able to decide 

 the question, or some clearer light may be obtained after closer ob- 

 servation of it next season. — G. S. Gibson ; Saffron Walden, Janu- 

 ary, 1843. 



449. On the dispersion of the Seeds of Oxalis Acetosella. I think 

 it is not generally known that Oxalis Acetosella has the power of 

 projecting its ripe seeds to a considerable distance from the plant. 

 Many of our native plants possess a similar power, such as Impatiens, 

 Cardamine, Ervum, Ulex, and other Leguminosse : in all these the 

 expulsion of the seeds is effected by the rapid opening and curling up 

 of the valves of the capsule ; in the Leguminosae the two valves be- 

 come spirally twisted, in Cardamine they form a flat coil. In Oxalis, 



