GRUBBIACEAE 



163 



other at the midrib, just leaving a thin white line over the latter uncovered. 

 Transpiration through the stomata is thus impeded in a double way, 

 firstly by the wool among which the stomata are hidden, and then by the 

 revolute margins which form two wind-sheltered channels, through which the 

 escaping air must pass before it reaches the outer atmosphere. The shrub is 

 consequently well able to endure short periods of extreme dryness of the air or 

 to withstand the exhausting effects of strong winds*. 



This feature of our vegetation, which is so frequent in many genera 

 and even entire families of the south western flora, often imparts great 

 uniformity and monotony of appearance to the landscape ; but when in flower, 

 the various shrubs and shrublets reveal their astonishing diversity. 



Fam. 9. Grubbiaceae. 

 (Plate 37, D, E; Figs. 81 a and b.) 



Shrublets with linear or lanceolate, persistent leaves. 

 Flowers in axillary, small glomerules, bisexual ; perianth 

 simple, 4-parted, the segments valvate, greenish, clothed 

 with long hairs on the back. Stamens 8, with slender 

 filaments and a short connective. Ovary inferior, 



Fig. 8 1 a. Grubbia. A. G. rosmarinifolia Berg. I. Transverse section of leaf. 7/1. 



2. Flower laid open. 10/1. 3. Transverse section of ovary. 20/1. 4. Fruit 



(from 3 flowers). 5. Same in long, section, two cells barren. 10/1. 

 B. G. stricta DC. Fruit in long, section, 4/1, the solitary seed entire. 



i -celled, with a central placenta, which is joined to a 

 septum in the bud. Ovules 2, pendulous, without 

 integument. Fruitlets compound, only 1 of each 

 inflorescence with a perfect seed. Seed with a thin 

 testa, derived from the outer layer of the nucellus ; 

 endosperm oily. 



* Even on the mountains of the South West occur occasional days on which the 

 relative humidity sinks as low as 25 °/ o . 



