134 



Influence of Habitat on Plant Habit. 

 Table III. 



HAIRY AND WOOLLY PLANTS. 



I )eserts 



Greece 



Stony places 



Deserts 



Mont. Calc, Spain 



Dry rocks 



Arid places, Syria 



Athens 



Fragments calcaireaux 



Deserts 



Spain. Algiers 



Maritime sands 



Alpine 



Mountains, Greece 



Ranunculus, 6 (variety) 

 Delphinium, li... 



7 



,. nanum 



Matthiola, 5 



Vella 



Farsetia, 1, 2, 3 

 Aubrietia 

 Alyssum, .5, G, 7 



8 



Sisymbrium , 32 . . . 

 Malcolmia, 9, 10 



11 



Cerastium latifolium 



„ tomentosum 



„ pedunculatum 



Now Volkens (fi), Lindman (1), Areschoug (8), Henslow (7), 

 and others have shown that hairy and woolly plants are more 

 abundant in the dryer parts of the Mediterranean, South Africa, 

 Australia, and South America. 



Moreover, within one genus one can often find that the moist 

 habitat species liave lost their hairs whilst the dry habitat forms 

 have retained them. This has been shown by St Alder for the 

 British species of Myosotis and Veronica (9), and for Oxalis in 

 Chili by Meigen (2 t). But as hairs are commonly used by plants 

 for at least 8 diffei-eut purposes it is not surprising that there are 

 many exceptions. 



The variation within the limits of one species according to 

 habitat are more convincing. On this point Linnaeus says, 

 " hirsutiem plantse ssepius exuunt a loco vel cultura" (10). A 

 very good example is the common Polygonum amphibium. 

 Buckman (11), Battandier (12), Henslow (7) give an account of 

 five different species which vary in this respect. To these I 

 would add the cases of Ranunculus (11) and Roemeria (1), which 

 are more hairy than usual in dry and sunny places. Mm. Vesque 

 and Viet (13) have also found that when plants are sown sparsely 



