PLANTS CULTIVATED FOR THEIR STEMS OR LEAVES. 121 



perennial ; stems numerous, spreading at the base, and 

 bent ; capsules 6 mm., with hairy partitions ; seeds 3 mm., 

 slightly hooked at the top. Linum angiistifolium. 



It may be seen how easily one form passes into 

 another. The quality of annual, biennial, or perennial, 

 which Heer suspected to be uncertain, is vague, especially 

 for the angustifolium ; for Loret, who has observed this 

 flax in the neighbourhood of Montpellier, says,^ " In 

 very hot countries it is nearly always an annual, and this 

 is the case in Sicilv accordincr to Gussone ; with us it is 

 annual, biennial, or perennial, according to the nature of 

 the soil in which it grows ; and this may be ascertained 

 by observing it on the shore, notably at Maguelone. 

 There it may be seen that along the borders of trodden 

 paths it lasts longer than on the sand, where the sun 

 soon dries up the roots and the acidity of the soil 

 prevents the plant from enduring more than a year," 



When forms and physiological conditions pass from 

 one into another, and are distinguished by characters 

 which vary according to circumstances, we are led to 

 consider the individuals as constituting a single species, 

 although these forms and conditions possess a certain 

 degree of heredity, and date perhaps from very early 

 times. We are, however, forced to consider them 

 separately in our researches into their origin. I shall 

 first indicate in what country each variety has been dis- 

 covered in a wild or half-wild state. I shall then speak of 

 cultivation, and we shall see how far geographical and 

 historical facts confirm the opinion of the unity of species. 



The covimon annual flax has not yet been discovered, 

 with absolute certainty, in a wild state. I possess 

 several specimens of it from India, and Planchon saw 

 others in the herbarium at Kew; but Anglo-Indian 

 botanists do not admit that the plant is indigenous in 

 British India. The recent flora of Sir Joseph Hooker 

 speaks of it as a species cultivated principally for the oil 

 extracted from the seeds; and Mr. C. B. Clarke, formerly 

 director of the botanical gardens in Calcutta, writes to 



* Loret, Ohservations Critiques sur Pluxieurs Plantes Montpellidraines, 

 in the Revue des Sc, Nat., 1875. 



