DICOTYLEDONES : POLYPETAL^ : CALYCIFLOR^. 



629 



Mamillaria has a spherical or cylindrical stem on which tubercules, arranged 

 spirally and bearing spines, represent the leaves. Echinopsis and Echinocactus 

 have angular ridges on which the tufts of spines grow, Cereushas an angular, 

 column»r, elongated stem. Phyllocactus and Kbipsalis have compressed leaf- 

 like stems. Opuntia and Nopalea have flattened stems composed of a suc- 

 cession of flattened ovate shoots. The Cochineal insect lives on Nopalea cocci- 

 nellifera. 



Cohort III. Myrtales. Flowers usually actinomorphic, 

 encyclic, epigynous or perigynous, with usually two whorls of 

 stamens, typically obdiplostemonous : gynaeceum syncarpous, with 

 usually a single style : leaves usually opposite. 



% 



V -^ 



Fio. 429.—^ Flower of Fuchsia : « pedicel ; / inferior ovary ; fc sepals, connate at the 

 base, forming a tube (r) ; o stamens ; g style ; n stigma. B Flower of Ep>lobium hirsutum 

 (letters as before). C Fruit of Epilobium after dehiscence; w outer wall; m columella 

 formed by the septa ; «o seed with tafts of hairs (nat. size). 



Order 1. Onagrace^. Flowers usually tetramerous throughout, 

 generally epigynous : antipetalous stamens sometimes suppressed : 

 ovary multilocular, with generally numerous ovules on axile 

 placentae : fruit a berry or a capsule ; seed without endosperm. 

 Calyx of ton petaloid, forming a long tube (Fig. 429 A^ r). 



V (Enothera biennis, the Evening Primrose, occurs on river binkg ; the seed has 

 not a tuft of hairs, and the flowers are yellow. Ei ilobium is the Willow Herb, 

 of which many species are common ; E. angustifolium, hirfnitum, and montanum 

 occur iu fields, hedges, and ditches ; the eeeds have a tuft of long hairs ; flowerti 



