1 7 8 FLOWERS OF THE ROADSIDES AND HEDGES 



are small or ephemeral. The leaf-blade is lobed and toothed, the 

 leaf glossy and glabrous. The bole has a smooth bark at first, which 

 becomes divided into longitudinal furrows, often twisted and grey in 

 colour. The trunk may divide. 



The flowers are white or pink, the inflorescence a corymbose cyme, 

 being cylindrical with a flat top. Each flower has 5 united sepals, 5 

 distinct white petals, 20 stamens, pink anthers becoming brown, and 

 they are attached to the margin of a basin. The style (i in this form) 

 is central with a broad stigma. The scent is due to trimethylanin. 

 The fruit is a haw or stone fruit, with i seed. The calyx is persistent 

 at the top of the fruit. 



The tree is often 15 ft. high. The flowering period is May and 

 June. A deciduous tree, it is perennial and increased by seeds. 



The honey is half-concealed, and is secreted by a ring at the base 

 of the flower. The stigma ripens first. The flowers are strong- 

 scented, and the smell is attractive to dung- and flesh-flies. The 

 stamens are not ripe when the flower opens. The outer are erect, the 

 inner bent inwards, the anthers below the stigmas. The stigmas are, 

 however, ripe and project in the centre, and the anthers ripen a few- 

 days after, opening inwards. The inner anthers when it is cold are 

 bent down below the stigma after opening, the outer overtop the 

 stigmas and are bent inward. But when it is fine the stamens bend 

 outwards and then the honey disk is visible. If insects visit the flower 

 they touch stamens and stigmas with opposite sides of the head and 

 cross-pollination follows, but in their absence and in wet weather self- 

 pollination is most probable. 



Sweet sap is exuded by the young shoots which insects seek. The 

 visitors are numerous: Anthophora, Bombus, Andrena, Odynerus, 

 TacJiydromia, Evipis, Microphorus, Pipiza, Rhingia, Eristalis, Helo- 

 philus, Xylota, Echinomyia, Sarcophaga, Onesia, Graphomyia, Mesem- 

 bnna, Cyrtoneura, Bibio, Dilophus, Attagemis, Anthrenus, Meligethes, 

 Anthraxia, Malachius, Telephorus, Asclera, Anaspis, Mordella, Clytus, 

 Grammoptera, Clythra, Halictus, Nomada, Eiicera, and Apis. 



The fruit is edible, and dispersed by birds, &c. It is therefore 

 spread largely by animal agency. 



Hawthorn is normally a sand plant living on a sand soil, but it 

 is usually enriched by some humus which is accumulated under its 

 own shade. 



The first stages of Gymnosporangium confusuni and G. clavarice- 

 forme grow on this plant. The second stage grows on Juniper in each 

 case. The leaves are galled by Eriophyes cratcegi, E. goniothorax, or 



