GROUP V. ANGIOSPERM.E ; DICOT^LEDONES. 517 



monlana, the broad-leafed Wych, or Scottish, or Mountain Elm. Celtis 

 australis, from Southern Europe and C. occidentalis, from North America, 

 are often cultivated as ornamental trees ; their flowers are polygamous 

 and are placed singly or several together in the axils of the oblique 

 acuminate leaves : the fruit is drupaceous. 



Cohort III. Amentales. The flowers, which are either dicli- 

 nous or dioecious, are arranged in catkins (amenta). The perianth, 

 when it is present, consists typically of 5 (-f ) segments ; or it may 

 deviate from the type so as to consist of four, (i.e. 2 + 2), or six (i.e. 

 3 + 3) segments : the stamens, when their position can be determined, 

 are superposed on the segments of the perianth for the reason given 

 in the case of Urticales (see p. 514). The ovary is either superior 

 or inferior, di- or tri-merous, with few ovules. The fruit (with the 

 exception of the Salicacese) becomes by abortion one-seeded, and 

 is indehiscent : the seed has no endosperm. The flowers are fur- 

 nished with bracts which often form investments for the fruit: 

 their arrangement in most of the orders 

 is as follows : in the axil of a scaly 

 bract (the bracts being arranged spirally 

 in the amentum) is a flower (&) with 

 two bracteoles a and /?, in the axil of 

 each of which is another flower with 

 two more bracteoles a' and yS' (Fig. 327). 

 The plants are trees and shrubs. 



Order 1. BETCLACE^. The flowers FI. 327 -Typical diagram o 



a group of flowers in the Amen- 



are monoecious, but in different catkins. taleg . d bract ; 6 the median 

 The 2 flowers have no perianth : the flower with its bracteoles, a and 



r , ft ; b' V the two lateral flowers, 



Ovary IS bllocillar, With two OVUles: ^th their bracteoles ' and p'. 



the fruit is one-seeded, indehiscent, 



without any investment : the bract is coherent with the two or four 

 bracteoles (the bracteoles a' are always absent) to form a three- or 

 five-lobed scale, which does not adhere to the fruit. 



Alnus, the Alder. In the $ amenta three flowers with four bracteoles 

 (a, /3, /3', p) occur in the axil of the bract, each flower having a perianth of 

 four segments, and four unbranched stamens. In the ? amenta the me- 

 dian flower is absent ; the four bracteoles coalesce with the primary bract 

 (Fig. 328 B, v *) to form a five-lobed woody scale which persists after the 

 fall of the fruit which is not winged. The <J catkins are borne terminally, 

 and the ? laterally on the highest lateral branch, on the shoots of the 

 previous year; they are not enclosed by bud-scales during the winter, 

 and blossoming takes place before the unfolding of the leaves. The leaves 

 have usually a arrangement : in A. incana, the White Alder, the leaves 



