Fam. 129. Compositae Giseke Sunflower Family 



Herbs, vines or shrubs; leaves alternate or opposite, exstipulate; flowers borne 

 in dense involucrate heads (the number of flowers in the head occasionally as 

 few as 1 or 2); axis and/ or receptacle of the head usually thicker than its stem 

 (peduncle), globose, cylindrical, conical, convex, flat or concave, near its base 

 usually invested with 1 or more series of persistent or deciduous bracts ("phyl- 

 laries") which partly enclose the head as it develops (when 2 or more series 

 of phyllaries are present, only the innermost subtend flowers; any similar bracteal 

 structures subtending the inner flowers of the head are called pales), the recep- 

 tacle either smooth or usually rough or pitted and in many genera chaffy, i.e., 

 with persistent or deciduous pales subtending some or all of the flowers (note 

 that bracteal structures subtending the most peripheral flowers are called phyl- 

 laries) ; flowers small, epigynous, protandrous, uni- or bisexual, fertile (producing 

 a viable fruit) or infertile; calyx absent or represented by a pappus (a series of 

 scales and/or bristles) at the tip of the achene near the base of the corolla if 

 a corolla is present; corolla sympetalous (composed of 4 or 5 coalescent petals), 

 rarely absent, quite diverse but usually taking one of the following forms or 

 types: (a) more or less radially symmetrical with a basal tube and a more or 

 less well-differentiated thicker (4- or) 5-toothed or -lobed limb; flowers with 

 such corollas are usually bisexual and are called disk flowers because they form 

 the central part ("disk") of the heads of the vast majority of the Compositae; 

 (b) bilaterally symmetrical, with a short basal tube and a flat beltlike or straplike 

 usually 3-toothed or -lobed ray-portion ("ray" is often used to mean the entire 

 corolla); flowers with this kind of corolla are pistillate, lack stamens and are 

 called ray flowers because when present they are peripheral in the head, the rays 

 projecting outward as extensions of the radiuses of the head, similar to spokes 

 of a wheel; (c) bilaterally symmetrical and more or less 2-lipped, with 2 teeth 

 and lobes on the ventral lip (the lip toward the center of the head) and 3 lobes 

 or teeth on the dorsal; such flowers are usually bisexual and are found exclusively 

 in the tribe Mutisieae (not in our area), which displays no other sort; (d) 

 bilaterally symmetrical, with a basal tube or funnel and a flat beltlike or strap- 

 like 5-toothed ray-portion ("ray" is often used to mean the entire corolla); flowers 

 of this kind are usually bisexual and are found exclusively in the tribe Cichorieae 

 (genera 49-52), to the exclusion of other sorts of flowers; androecium of (4 or) 

 5 stamens, alternate with the corolla lobes or teeth; filaments separate, adnate 

 to the lower part of the corolla limb and tube but free for part of the length 

 above (lightly coalescent to each other in Ambrosia, Xanthium and Iva); anthers 

 flat, elongate, 2-celIed, coalescent to form a short tube around the style (loosely 

 coherent or nearly free in Ambrosia, Xanthium and Iva); pistil solitary, composed 

 of 2 carpels (1 being abortive), the ovary inferior, uniloculate; style columnar 

 and usually exserted late in anthesis, usually 2-branched, the branches often 

 arcuate-diverging, usually each slightly dorsiventrally flattened and often with 

 linear stigmatic areas (stigmatic lines) along proximal parts of the 2 thinner 

 edges, and near the stigmatic lines often with a variously rough or hairy portion 

 and occasionally distally from this an appendage (meaning that portion of the 

 style branch, if any, distal to the stigmatic line); fruit an achene, either columnar 

 or prismatic or conical or often flattened or compressed (the flattening or com- 

 pression said to be "lateral" when the plane of the achene is radial and includes 

 the axis of the head; "dorsiventral" when the plane of the achene is perpendicular 

 to a plane passing through the axis of the head, and in a dorsiventrally compressed 

 achene the side toward the center of the head is said to be "ventral", that toward 

 the periphery of the head "dorsal"); ovule solitary, basally attached, anatropous; 

 integument solitary. 



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