DIPLOPAPPUS LINARIIFOLIUS. SANDPAPER STAR- WORT. I 5 



having perhaps been made acquainted with it by his correspondent, 

 the Rev. John Bannister. Linnaeus knew it as Aster linariifolius, 

 Michaux as Aster rigidtis, and Nuttall included it in his genus 

 Chrysopsis as C linainifolia. The genus Diplopcxppus was founded 

 by Cassini in a paper pubHshed in a Paris magazine in the early 

 part of the present century. The genus Aster is so very large 

 that though the distmction between it and Diplopappus is small, 

 the division, if at all well founded, must be acceptable to students. 

 It will be noted by those fond of accuracy that the common con- 

 struction of the specific name, linariifolius — that is, "leaves like 

 or belonging to the linaria" — is not according to Ladn rules, 

 Linaria should form its genitive linariai = linarisefolius, and we 

 have to acknowledge our ignorance of any valid reason for the 

 orthography in general use. 



The species affords a very pretty botanical lesson in the devel- 

 opment of its axial buds to branches, and these again to flowers. 

 As we see in our plate, no buds grow from the axils of the lower 

 leaves, but gradually a few axillary leaves appear as the stem 

 elongates, undl the latter is suddenly suppressed, when the axial 

 growths become stronger, and while some of them never become 

 more than litde branches, others go on to complete flowers. The 

 sudden arrest of growth in the main stem accelerates that of the 

 branchlets, and we can see that it was this sudden stoppage of 

 growth at the apex which gave the graded impulse downwards, 

 and which resulted in the growth of the axial buds. Precisely 

 the same effect is produced in any growing shoot by artificially 

 arresdng its growth^that is, by pinching out its terminal bud. 

 We know that these sudden arrests or sudden acceleradons of 

 growth are the foundation of many wonderful changes in the 

 forms of flowers and the general characters of plants; but atten- 

 tion having but recendy been drawn to these simple facts, the 

 laws which induce these rythmic growths are not yet understood. 

 Besides furnishing a valuable lesson in botany, it is a beauuful 

 plant ; and those who grow it in gardens generally esteem it 

 highly on this account. It is one of the last of floral charms to 



