616 REV. GEORGE HENSLOW ON THE ORIGIN OF 
a fact well known and often commented upon. Thus Guillard observes :—** La Feuille 
aisselióre est surhaussée par adhérence à son axillaire’’*. Bravais also alludes to les 
soudures des feuilles as of common occurrence f. 
The elevation of the bracts in the bracteate scorpioid inflorescences is very slight; 
while the shifting of their positions is quite in accordance with the normal change 
from the 2 spiral to the distichous arrangement in the Cherry-Laurel, Ze In that 
plant, whenever a shoot grows vertically the leaves are mostly to be represented by Z or $ ; 
but when (as is their usual habit) the branches grow horizontally, then the leaves are 
distichous. Similarly other changes are not at all unfrequent. Leaves may be 5 at the 
base, $ higher up, and 35; above, as Payer describes them in Echinocactus ; not to add the 
fact, on which the thesis of this paper is based, that the alternate arrangements have 
arisen out of opposite and decussate. ! 
This common fact, of a change of position of a leaf, proves that the point of emergence 
of a leaf-papilla can easily be shifted according to circumstances of growth; thus gravity 
is possibly an active eause in producing the distichous arrangement in dieotyledons with 
horizontal branches. In the case of the scorpioidal inflorescence, perhaps some other 
influence may determine the emergence of the bracts and flowers being all on one side 
of a diameter drawn across the flower-stalk; for it will be observed that the two rows 
of bracts, instead of being 90° apart, are now diametrically opposite to each other, 4. e. 
each bract has passed through an angle of 45° towards the side which bears the flowers. 
Similarly with regard to the flowers, instead of being in two vertical rows 90° apart, as 
in Lathrea, the rows have become drawn nearer to each other, having passed through 
an angular distance together of about 30°. This approximation is apparently fore- 
shadowed in the strong inclination to a secund arrangement in Lathrea. 
Thus, I believe, do we obtain the characteristic inflorescence of those genera Ss 
Boraginee and Solanee of which the scorpioidal inflorescence consists of two rows of 
flowers together with two rows of bracts—such, for example, as of Symphytum, Borago, 
Iycopsis, and Hyoscyamus. 
In Myosotis the bracts have all become completely arrested, so that there is eet | 
left but the two parallel rows of flowers; and as the pedunele or morphological axis 
elongates, the flowers become separated. 
There yet remains a further observation to be made. The pair of scorpioid racemes 
which terminate the axis of Myosotis and other species of the Boraginee often have the 
appearance of dichotomy; sometimes, indeed, again and again repeated, as in Heliotropium, 
and not infrequently with a flower situated in the fork, so that the two branches curl in 
opposite directions. This appearance has, I believe, been the source of an error in the 
usual interpretation. Ifa large number of specimens be examined, the above description 
will be accurately true for some of them; but more frequently the lowermost flower 
* Bull. Soc. Bot. de Fr. iv. p. 933. ie 
+ Ann. des Sc. Nat. 2° sér. vii. p. 298. As further references to the uplifting of bracts the reader is — to: e um 
Paver, ‘Éléments de Botanique, p. 116. Wanwze, Botanisk Tidskrift, 1869, Bind 3, Tab.1; also, Viđensk. 
Belsk. Skr. 5 Række, Naturvidenskabelig., Afd. Bd. 10; French résumé, ‘Recherches sur la ramification 
Hes or p. xxii, Barrow, “ Sur les lois de l'entrainement dans les — eegener ` P 
