130 ME. C. DAEWIN ON THE ACTION OF SEA-WATEE 



every part except the very sutures, as in G. Andrewsii, G. crinita, 

 &c. Examining some other genera, we found this to occur also 

 in JBartonia, Muhl. (Centaurella, Michx.) ; equally so in both 

 species, B. tenella and B. verna. In the former species, in which, 

 as in Oholaria, four re-entering angles render the cell cruciform, 

 the resemblance to Oholaria is striking and complete, as you will 

 see from the enclosed sketch of a transverse section of the ovary 

 of B. tenella. The only anomaly of Oholaria as a true Gentianea 

 which remains, is the imbricative (instead of convolutive) aesti- 

 vation of its corolla ; — of which no parallel instance is known, so 

 far as I am aware. It may however be expected to occur ; for 

 useful and reliable as the aestivation of the corolla often is, as an 

 ordinal mark, it is seldom altogether constant. 



I think I once mentioned to you an exception of this sort, or 

 rather a variation, which occurs in a family in the arrangement of 

 which you have employed aestivation of the corolla to great ad- 

 vantage, viz. the Scrophulariaeecje, in characterizing the suborders 

 (as I would suggest they ought not to be called) Antirrhinidece 

 and Bhinanthidece. The same accurate observer, Mr. Clark, long 

 ago showed me that this character occasionally failed in Mimulus } 

 especially in M. ringens and M. moschatus, which almost as fre- 

 quently present the aestivation of the Bhinanthidece (i. e. have some 

 part of the lower lip exterior) as that of the Antirrhinidece, to 

 which the genus belongs. Last summer I noticed a second ex- 

 ception of the kind in sbPentstemon (P. heterandrum, Torr. & Gray, 

 in Beckwith's Report of a Pacific Railroad Survey), which besides 

 the anomaly of having the fifth stamen sometimes antheriferous 

 and sometimes sterile, had also, in about half of the flowers 

 examined, the lateral lobes of the corolla external in the bud, and 

 covering the two posterior lobes as well as the anterior one. 



On the Action of Sea- water on the Germination of Seeds. By 

 Chaeles Daewin, Esq., Vice-Pres. E.S., E.L.S. &c. 



[Eead May 6th, 1856.] 



Dtjeing the spring of last year it occurred to me that it would be 

 worth while, in relation to the distribution of plants, to test how 

 long seeds could endure immersion in sea-water, and yet retain 

 their vitality. As far as I knew, this had not been tried by bota- 



