132 



Influence of Habitat on Plant Habit. 



was suddenly interrupted, as I was urgently requested by Mr 

 Thiseltou Dyer to go to Sierra Leone, so that I was unable to finish 

 the Compositae which I had commenced. 



The first habit of which I took note, the " rosette-type," 

 consists of those plants in which all the leaves are radical and the 

 stem forms no internodes whatever. 



I found 33 plants belonging to this type in the 230 examined. 

 These are shown in the first table. 



Table 1. 



ROSETTE PLANTS. 



Cerastium macranthum 

 „ scaposum . . . 

 ,, campanulatum 

 Iberis, 19* 

 Lychnis alpina 

 Thlaspi, 6, 8, 10, 20, 21, 23 

 Sisymbrium, 32 

 Arabis, 6, 10, 11, 12, 13 

 Cardamine, 13, 14, 15 

 Alyssum, 5, 6, 7 

 Diplotaxis, 3, 5, 6t ... 



10 



11 



13 

 Sinapis, 10 

 Brassica, 24 ... 

 Lepidium, 21, 22, 23... 



Rocks, Algiers 



Rocks, Crete 



Sand, Naples 



Dry places 



Rocks ? 



Rocks 



Desert 



Rocks 



Rocks, Alps 



Athens 



Exposed places 



Sandy waysides 



Seaside 



Midian Desert 



Calcaire aride 



Algeria 



Stony mountains. 



It will thus be seen that of these 33 species 16 grow on rocks, 

 13 in dry countries, and 4 in sandy places. 



All these habitats involve more than an average amount of 

 exposure, or in other words, the plants growing- in them are 

 subjected to more than tlie usual amount of transpiration ; I have 

 myself noticed the abundance of the rosette type of plant in 

 such places, e.g., as the " baiTancos" of the Canary Islands, on the 

 dry sandy shores of South-Eastern Madagascar, at the junction 



* The numbers are species in Nyman's Conspectus, 

 t The rosette form in these 3 occurs only in exposed habitats. 



