COMPOSITE FAMILY. 223 



I ! Chaffy receptacle ; scales of the involucre dry and very stiff, in many series, often 



colored. 

 68. XERANTHEMUM. Heads large and solitary, long-peduncled. Involucre campanu- 



late or cylindrical, the scales spreading, the outer ones shorter. Akene slender, 



with a minute crown. Hoary. 



1 1 1 Chaffy receptacle; scales of the involucre green, few, and rounded. 

 81. IVA. Heads small and few-several-flowered, the outer 1-4 pistillate and fertile, with 



a small tubular corolla or 0, the others staminate with a funnel-form, 5-toothed corolla. 



Anthers nearly separate. Akenes ovoid or lenticular. Pappus 0. 

 = = Pappus none at all to the outer pistillate and fertile flowers, but of some slender 



bristles in the central and perfect, yet seldom fruit-bearing flowers ; scales of 



the involucre woolly. 

 20. FILAGO. Heads small, crowded in close clusters, of many Inconspicuous flowers, each 



fertile pistillate flower in the axil of a thin and dry chaffy scale, and with a very 



slender, thread-like corolla ; the central flowers with a more expanded 4-6-toothed 



corolla. Low herbs, clothed with cottony wool ; leaves entire. 



= Pappus of all the flowers composed of bristles (but caducous in Grindelia); no 



chaff among the flowers. 

 1 Cottony-white herbs. 



81. GNAPHALIUM. Small heads (often clustered) of many whitish flowers, surrounded 

 by an involucre of many ranks of dry and white or otherwise colored (not green) 

 searious and persistent scales woolly at base ; the flowers all fertile, the outer ones 

 with pistil and very slender corolla, the central ones perfect and with more expanded 

 5-toothed corolla. Pappus a row of very slender and roughish bristles. 



(22) ANTENNARIA. Like Gnaphalium, but the plants dkecious. Staminate flowers with 



a simple style, but the ovary sterile, and their pappus of stouter bristles which are 

 thickened at the summit, and there more or less barbed or plumed ; pappus of fer- 

 tile flowers united and falling together. 



28. ANAPHALIS. Heads dioecious or nearly so. Pappus not thickened or united. Fer- 

 tile heads usually bearing a few perfect but sterile flowers in the center. Otherwise 



like Antennaria. 



I [ Not cottony. 



(9) GRINDELIA, which is sometimes rayless, may be sought here (p. 226). 



25. HELICHRTSUM. Heads rather large, terminating the branches singly, the pistillate 

 flowers few and often in a single marginal row. Involucre dry and chaff-like, not 

 cottony, the scales stiff and spreading, often colored. 



19. PLUCHEA. Heads many-flowered, the central flowers perfect but sterile, these few, 

 with a 5-cleft corolla ; all other flowers pistillate and fertile, with a thread-shaped trun- 

 cate corolla. Involucre imbricated. Anthers with tails. Akenes grooved. Pappus 

 in a single row. Strong-scented herbs, near the coast. 



61. ERECHTITES. Heads of many whitish flowers, with a cylindrical involucre of many 

 narrow and naked scales in a single row ; outer flowers with very slender corolla : 

 inner with more open tubular corolla. Akenes narrow ; pappus of copious, very fine 

 and soft, naked, white hairs. Bank coarse herb. 



f) ERIGERON. One species has such short and inconspicuous rays that it may b 

 looked for here (p. 225). 



H. -H- Only one kind of flowers in the head. 



-~ Scales of the involucre dry and papery or scarioiis, often colored (i.e., not green], 



not withering, in many ranks ; many flowers in the head. 

 11 Plant dioecious : head containing only staminate or pistillate flowers. 



22. ANTENNARIA. Pistillate flowers with very slender corollas and a pappus of long and 

 very fine, hair-like, naked bristles ; the staminate (with a simple imperfect style), 

 with the pappus of thicker bristles enlarging and somewhat plumed or barbed at theii 

 summit. Leaves and stems cottony. 



(23) ANAPHALIS. See above. 



