THE VARIETY OF PLANT LIFE 



105 



Family, while annual flowers are numerous in the Primrose, Mint 

 and Composite Families. Food plants are found in the Huckle- 

 berry, Morning Glory, Potato and Goud Families. 



The sub-class of monocots is conspicuous for the absence of 

 tree species, which is to be expected from their type of stem struc- 

 ture; it abounds in tropical members, many of them of spec- 

 tacular leaf and flower characteristics. About 35,000 species of 

 Monocots are grouped into some 30 families. There are numerous 



Fig. 



A 1 C 



73. — Grasses have developed a highly specialized type of wind-pollinated 

 flower; Kentucky blue grass (A), timothy (B), wheat (G). 



families of aquatic plants, used in garden pools and aquaria; 

 these include the Cat-tail, Pondweed, Arrowhead, Tape-grass, 

 Duckweed and Water Hyacinth Families. Some of these have 

 minute wind-pollinated flowers, as in the Cat-tails where the tiny 

 brownish flowers are clustered into cylindrical spikes; while 

 others have conspicuous and beautiful blooms as the Pickerel 

 Weeds, Water Hyacinths and Arrowheads. 



The Monocots include one of the most widespread and valu- 

 able of all plant groups — the Grass Family. Grass species have 

 developed a highly specialized type of wind-pollinated flower (fig. 

 73) which lacks the usual colored corolla. An effective habit of 



