parti] = THE MECHANISMS OF FLOWERS. 469 
Orv. VERBENACEZ. 
; Aigiphila elata, Sw., and 4%. mollis, H. B. and Kth., are con- 
_ spicuously heterostyled. 42. obdwrata “ probably was once hetero- 
_ styled, and has since been rendered dicecious by the pistil in the 
one form and the stamens in the other having become functionless 
and reduced in size” (Darwin, 167, p. 124). 
Verbena officinalis, L.,is adapted for fertilisation by bees (590, 
111., and 609). 
The flowers of a Lantana in South Brazil are, according to Fritz 
Miiller, yellow on the first day, orange on the second, and purple 
- on the third. Some butterflies visit the yellow and orange flowers, 
- some exclusively the yellow, none the purple. So this change of 
colour increases the conspicuousness of the plant, and at the same 
time saves many useless visits (560). 
Ocimum, L.—In this genus the Labiate type of flower is reversed, 
| the stamens and style lying upon the under lip, while the upper 
_ side of the tube lodges the honey, which is protected by hairs on 
_ the superior stamens. Therefore the stamens first curve upwards, 
the style downwards, and afterwards in the contrary direction; 
which is the reverse of what occurs in Teucrium, forinstance. The 
fertilisers are bees of the genera Anthidium, Apis, Bombus, and 
| Halictus (178, 360). 
Orv. LABIAT A. 
Plectranthus fruticosus, LiHér.—The reproductive organs lie 
below the entrance into the honey-receptacle, which is a spur-like 
_ development of the base of the corolla. In the first stage the 
style lies with unripe stigmas between the stamens; in the 
second the stamens have spread apart, and the style with 
outspread stigmas stands alone in the way of insect-visitors (360). 
: 336. LAVANDULA VERA (L.), D. C.—The spikes of small blue 
_ flowers attract many insects, especially bees, by their strong scent, 
and supply abundant honey. The tube is 6 mm. long, and the 
nectary resembles that of Thymus in size and position. The 
stamens, which lie in the inferior side of the tube, overtop 
the stigmas, but the well-marked proterandry insures cross- 
fertilisation. 
(1) Anthophora quadrimaculata, Pz. 9 ¢, ab.; (2) Osmia nea, L. g, 
freq. ; (3) O. rufa, L. 9, s.; (4) Megachile pyrina, Lep. (fasciata, Sm.), ¢, 
