244 ANGIOSPERMAE—DICOTYLEDONES 



(4) The flowers are pendulous, so that the upper lip is directed point downwards 

 and functions as a lower lip (Salvia nutans Z.). The second type includes the typical 

 labiate flowers, in which the upper lip forms a roof for the stamens and pistil. In 

 these species nectar is always secreted on the lower side of the flower, and pollen 

 is scattered on the insect's back. 



Many South American species (Salvia gesneraeflora Lindl. et Paxl., and 

 S. splendens Ker-Gawl.) are ornithophilous. Besides hermaphrodite flowers, female 

 ones are frequently present, distributed gynomonoeciously or more rarely gynodioe- 

 ciously. Gynodioecism is not infrequent in England ; e. g. F. Darwin, and subse- 

 quently J. C. WiUis (Proc. Phil. Soc, Cambridge, vii, 1892, viii, 1893), often found 

 flowers of Origanum vulgare L. with reduced stamens. He also observed gynodioecism 

 in Thymus Serpyllum L., Nepeta Glechoma Benth., N. Cataria Z., Prunella vulgaris 

 Z., and in the following garden plants : Micromeria Juliana Benth., Nepeta longiflora 

 Vent., Hyptis pectinata Poit., Bystropogon punctatus L He'rit., Mentha aquatica Z., 

 Satureia hortensis L., and S. montana Z. 



Schulz sums up his investigations ('Beitrage,' II, pp. 138-41) somewhat as 

 follows. — 



The size of the hermaphrodite flowers in most labiates varies greatly in the same 

 station, and in some species even on the same plant. Several, generally two, definite 

 sizes are to be seen in many districts in the flowers of some species : these are 

 either entirely distinct or connected by an occasional transition form. In other 

 districts only one of these sizes is to be found, while in some places it becomes 

 impossible, on account of the great number of transition forms, to distinguish definite 

 flower-sizes at all. The hermaphrodite flowers of most of the species treated by 

 Schulz are more or less protandrous, but a few, such as Stachys annua Z. and 

 Galeopsis ochroleuca Lam., always bear completely homogamous flowers. Some 

 species, e.g. Salvia pratensis Z., Prunella grandiflora /af^., P. vulgaris Z., and Ajuga 

 reptans Z., vary between feeble protandry and homogamy ; indeed, in the case of the 

 first-named species, this often occurs in flowers on the same plant. Automatic self- 

 pollination always takes place in some of the few species with homogamous or feebly 

 protandrous flowers, but is rendered very difficult in others by the unfavourable 

 relative positions of the stigma and anthers. In markedly zygomorphous flowers 

 the stamens are almost in the same plane, and lie near or quite close to the upper 

 lip, or are at least just in front of it. The anthers are introrse, and dehisce in 

 descending order on each side of the median plane, i.e. they turn their pollen-covered 

 surfaces towards the lower lip. In flowers of practically actinomorphous type, e. g. 

 those belonging to the genus Mentha, the stamens are not crowded together into 

 nearly the same p'ane in front of the upper lip, but are disposed according to their 

 insertions in front of the calyx-teeth. The anthers are attached by conveniently 

 flexible insertions to the filaments, and are almost horizontal, being so placed that 

 they turn their tips to the margin of the flower, and become covered above with 

 pollen. Towards the end of dehiscence, or after its completion, they usually become 

 curved, and their two ends project slightly downwards. The larger insect visitors 

 strike in both types, almost without exception, against the pollen-covered surfaces of 

 the anthers ; in certain sf)ecies of Salvia, however, a special lever-like mechanism is 

 necessary for pollination, on account of the breadth of the mouth of the corolla. 



