NOTES AND EXHIBITS. 415 



the common involucre is thrown into confusion, its bracts being 

 irregular in size and contorted; the prolification of the inflores- 

 cence by miniature buds is increased, the strain on the axis 

 causing an apparent reversion of their pedicels. The examples 

 exhibited were taken from plants in the Sydney Botanic Gardens, 

 grown from seeds presented by Mr. Greaves, of Bondi, who has 

 for some years been growing this strain of Marigold, e.g., the 

 double-flowered example shown in the second stage. Modern 

 workers have given a considerable amount of attention to the 

 question of heredity as a factor in the production of these tera- 

 tological mutations. The consensus of opinion is that heredity 

 is admitted, but is largely controlled by external conditions con- 

 ducive to forced growth, such as over-luxurious food, or a copious 

 supply of water after prolonged dryness. Celosia argentea var. 

 cristata, "Cockscomb/' is cited by several authors as an example 

 of a plant which requires a generous diet to enable it to sustain 

 its fasciated "comb." As a modicum of evidence in favour of 

 hereditability, it may be noted that a series of plants from un- 

 selected seeds of Calendula officinalis growing side by side with 

 those from Mr. Greaves' strain, under similar cultural conditions, 

 produced no abnormalities; while the majority of the plants 

 grown from Mr. Greaves' seed were more or less affected. The 

 specimens in the first three stages were collected by Mr. E. N. 

 Ward from a single plant, and that in the fourth stage from a 

 plant on which an example in the first stage was also growing. — 

 Platylohiwin formosum Sm., (Wentworth Falls; A. A. Hamilton: 

 January, 1915), showing leaf -variation resultant from environ- 

 ment. Example No.l, with small crowded leaves, was found 

 growing on a dry ridge. No. 2, with large, distant leaves, grew 

 in a moist gully below: and those in the intermediate stages were 

 collected on the slope between the ridge and the watercourse. — 

 Eriostemon hispidulus Sieb., (Springwood; A. A. Hamilton; Sep- 

 tember, 1934), showing leaf-variation. The leaves are oblong, 

 linear or spathulate; toothed or entire marginally; narrowed at 

 the base into a petiole, or broadly sessile; and range from ^ to 

 li inches long. All the examples were growing on a sandstone 

 ridge under apparently similar environmental conditions. — 

 Acacia implexa Benth., (Glenbrook; A. A. Hamilton; December, 



