30 THE LEAF 



In the sycamore, the base of the petiole is hollowed out 

 into a socket to protect the bud of the season (Fig. 20). 



34. Leaf Attachment. When the petiole is wanting 

 altogether, as is often the case, leaves are said to be sessile, 

 that is, seated on the stem, and their bases are described 

 by various terms suggestive of the mode of attachment. 

 You can frame your own definition of these terms by an 

 inspection of the accompanying figures, or better still, of 

 some of the sample plants named in connection with 

 each. 



Clasping (Fig. 21): Wild lettuce (Lactuca), chicory, sow 

 thistle (Sonchns\ poppy, stem leaves of turnip, mustard, etc. 



Decurrent (Fig. 22) : Thistle, sneezeweed (Helenium 

 autumnale\ comfrey (Symphytum). 



Connate (Fig. 23): The upper leaves of boneset (Eupa- 

 torium perfoliatum) and trumpet honeysuckle (Lonicera 

 semperuirens). 



Perfoliate (Fig. 24) : Bellwort (Uvularia perfoliata). 



Peltate, or shield-shaped (Fig. 25): Castor oil plant, 

 trop^olum, May apple (Podopkyllum), water pennywort 

 (Hydrocotyle). 



Equitant (Fig. 26) : Iris, sweet flag (Acorus calamus}, 

 blackberry lily (Belamcanda chinensis). 



35. The Use of Botanical Language. These terms and 

 those which follow are not to be learned by heart, but are 

 given here merely for convenience of reference. Botanists 

 have invented a number of useful terms for describing 

 things briefly and accurately, and while they are not to be 

 regarded as of any importance in themselves, it is impos- 

 sible to get along without some knowledge of them ; for 

 besides furnishing a sort of universal vocabulary, intelli- 

 gible to botanists everywhere, they enable us to say in two 

 or three words what it would otherwise require as many 

 lines or perhaps paragraphs to express. In other words, 

 they are a sort of labor-saving device which every botanist 

 must learn how to use, as no good workman can afford to 

 be ignorant of the tools of his profession. 



