- PART III, | THE MECHANISMS OF FLOWERS. 149 
more fertile when legitimately fertilised. As a rule the pollen- 
- grain failed to develop its pollen-tube when on the stigma of a 
flower of its own kind (157). 
| In Linum perenne illegitimate pollination of the ine Styled 
form was quite unproductive, and in the short-styled form very 
nearly so; in both forms, legitimate pollination led to full fertility 
in three cases out of four. Hildebrand found that in this species 
short-styled flowers were quite infertile with their own pollen, 
with that from another flower on the same plant, or from any other 
short-styled flower; but invariably fertile to pollen from a long- 
styled flower (339, 340). 
[In Linum Lewisti, Pursh. (L. Sibiricum, D.C.), according to 
_ Planchon, each plant bears flowers of three kinds, one long-styled, 
_ one short-styled, and one with styles and stamens of equal length ; 
- that is to say, it is trimorphic, though not in the same sense that 
_ Lythrum Salicaria is so. Dr. Friedrich Alefeld enumerates twenty- 
nine dimorpbic species of Linum, all natives of Europe, Asia, or 
- North Africa; while all the species from North and South America 
and from the Cape are monomorphic (1). (Cf. Darwin, 167.) 
Radiola linoides, D.C. (R. miliegrana, 8m.), is visited by minute 
_ Diptera (590, IL). 
_Erythroxylon is dimorphic. 
a 
i 
Ord. MALPIGHIACEZ. 
Camarea, St. Hil., and Janusia, A. Juss., according to Adr. de 
Jussieu, have cleistogamic as well as normal flowers; Aspicarpa 
ureus, Rich., occurs with only cleistogamic flowers (531); Gaudi- 
chaudia, H. B. and K., also is placed among cleistogamic forms by 
Kihn (399). 
In Bunchosia gaudichaudiana the glands on the exterior of the 
valyx seem not to be protective in function. They are visited by 
4 various bees (Tetrapcedia and Epicharis), which in feeding on them 
dust the under surface of their bodies with pollen, with which they 
_ cross-fertilise other flowers (360). 
Lie he Teg RR IRE ah 5 eh ty i a mr 
_ t a5 - . 
Orp. GERANIACEZ. 
Tribe Geraniee. 
a 76. GERANIUM PALUSTRE, L.—The structure of this flower was 
thoroughly described and figured by Sprengel, who, however, 
] observ ed no insect-visitors. In sunshine the flowers expand their 
