LESSON 30.] HOW TO STUDY PLANT8. 183 



fiiinily. The families are so numerous, and so generally distinguishK 

 able only by a combination of a considerable number of marks tha^ 

 the student must find his way to them by means, of a contrivance 

 called an Analytical Key, This Key begins on p. 12. 



527. It t^es note of the most comprehensive possible division of 

 plants, namely those " producing true flowers and seeds," and those 

 " not producing flowers, propagated , by sporgs." To the first of 

 these, the great series of Ph^nogamous or Flowering Plants, 

 the plant under examination obviously belongs. ,, 



628. This series divides into those " with wood; in a circl^ 91 in 

 concentric annual circles or layers around a central pith, netted-y^ined 

 leaves, and parts of the flower mostly in fives or fours," — to which 

 jpight be added the dicotyledonous embr^p, but that in the present- 

 case is beyond the young student's powers, even if |;he fruit were at 

 hand; — and into those "with wood in separate threads, scattered 

 through the diameter of Ihe stem, not in a circle," also the " leaves 

 mostly paraUel-veined, and parts of the flp.wer almost always in. 

 threes, never in fives." Although the hollo wness of the stem of the 

 present plant may obscure its internal structure, a practised hand, 

 l)y throwing the light through a thin cross section of the stem under 

 the glass, would make it evident that its woody bundles were all in 

 a circle near the circumference, yet this could hardly he expected 

 of an unassisted and inexperienced beginner. But the two other 

 and very obvious marks, the netted-veined, lea,ves, and .Jjhe number' 

 five in both calyx and corolla, certify at once iha,t the plant belongs, 

 to the first class. Exogenous or Dicotyledonous .Plants. 



529. We (Should now look at the flower more particularly, so 

 as to make out its general 

 plan of structure, which we 

 shall need to know all about 

 as we go on. We observe 

 that it has a calyx of 5 

 sepals, though these are apt 

 to fall soon after the blossom 

 opens ; that the 5 petals are sss 



borne on the receptacle (or common axis of the flower) just above 

 the sepals and alternate with them ; that there are next borne, a 



FIG. 358. A flower of a Buttercup (Ranunculus bulboBus) cut through ftom top to bottom, 

 and enlarged. 



