102 COMMON CANADIAN WILD PLANTS. 



DIP'SACES, Tourn. Teabkl. 

 D. sylves'tris. Mill. (Wild Teasel.) A stout, coarse, 

 prickly plant, not unlike a thistle in appearance. Flowera 

 in oblong very dense heads, bluish. Corolla 4-cleft. Sta- 

 mens 4, on the corolla. Bracts among the flowers terminat- 

 ing in a long awn. Leaves generally connate.— -Roadsides 

 and ditches. Very common in the Niagara district, but 

 found also elsewhere. 



Order L. COMPOS'IT.ffi. (Composite Family.) 

 Flowers in a dense head on a common receptacle, and sur- 

 lounded by an involucre. Calyx-tube adherent to the ovary, 

 its limb either obsolete or forming a pappus of few or many 

 bristles or chaffy scales. Corolla either tubular or with one 

 side much prolonged (strap-shaped or ligulace). Stamens 

 usually 5, on the tube of the corolla, their anthers united 

 (syngenesious). Style 2-clef t. (See Part I. , sections 60-62, 

 for examination of a typical flower.) 



The heads of flowers present some variety of structure. 

 All the flowers of a head may be tubular ; or only the central 

 ones or disk-flowers, as they are then called, may be tubular, 

 whilst those around the margin, then known as ray-flowers, 

 are ligulate or strap-shaped. Or again, all the flowers may 

 be strap-shaped. It is not unusual also to find a mixture of 

 perfect and imperfect flowers in the same head. 



The bracts which are often found growing on the common 

 receptacle among the florets are known as the chaff. When 

 these bracts are entirely absent the receptacle is said to be 

 naked. The leaves of the involucre are called its scales. 



Artlflclnl Synopsis of llic Genera. 



Suborder I. TUBULIFLO'RiG. 

 Heads either altogether without strap- shaped corollas, or 

 the latter, if present, forming only the outer circle (the ray). 

 Ray-flowers, when present, always without stamens, and 

 often without a pistil also. 



