64 THE JOURNAL OF BOTANY 



THE MUSS^NDAS OF MADAGASCAE. 



By H. F. Wernham, B.Sc. 

 (Department of Botany, British Museum.) 



In a recent paper (Journ. Bot. 1913, p. 233) I pointed out the 

 possible significance of the relative size of the limb and tube of 

 the corolla in the genus Mussanda. In the case of species with 

 one of the calyx-lobes developed as a foliar attractive organ, the 

 limb is relatively insignificant. In the case of the Mussanda 

 species found in Madagascar and the Mascarenes — all endemic 

 save one [M. arcuata) — the corolla-limb is relatively large, and the 

 calyx-lobes subequal {^Landia), none being amplified into the 

 foliar organ characteristic of, e. g., M. luteola. 



M. elegans is the only continental African species known in 

 which the corolla-limb is amply developed and the calyx-lobes 

 invariably subequal ; and it is thus worthy of note that the two 

 conditions of the corolla-limb in question are in significant corre- 

 spondence with two respective areas of distribution, viz., con- 

 tinental Africa and the islands in question. A further interesting 

 point in the same connection is the fact that M. arcuata, which is 

 transitional from the aspect of the corolla-limb and the calyx- 

 lobe development (Journ. Bot. 1913, p. 233), occurs widely in 

 both the areas named. 



Again, all the species now concerned appear to be erect in 

 habit, either shrubs or trees, with the exception of M. arciiata. 



All the eighteen species dealt with in the present paper are 

 endemic in Madagascar, with four exceptions, namely, ill. arcuata, 

 Poir., just mentioned, which occurs in Mauritius and Bourbon, as 

 well as in Madagascar ; M. mauritiensis (p. 66) and M. Stadmannii 

 Michx. (p. 66), confined to Mauritius; and 71/. Landia Poir., ex 

 hb. Justice Blackburn, the locality of which is in doubt, but pro- 

 bably Mauritius. 



Key to the Species. 



Plants glabrous, or almost so, including the flowers ; corolla- 

 tube, 2"5 cm. long at most, usually much less, occasionally 



puberulous externally along 5 obscure ridges 1. arcuata. 



Plants not glabrous. Corolla-tube over 3 cm. at least, usually 

 over 4 cm., never glabrous. 

 Pubescence on principal leaf-veins adpressed, or mostly so. 

 Calyx-lobes + rigid, appreciably broad, not subsetaceous. 

 Leaves not glabrous above. 



Leaves not oblanceolate (except in M. asperula) ; 



+ rough above with very short hairs, usually 



much over 10 cm. long. 



Leaves broadly oval, shortly acuminate at most, 



barely twice as long as broad. 



Corolla-tube about four times as long as lobes 



2. tricJiophlebia. 

 Corolla-tube less than three times as long as lobes. 

 Calyx -lobes linear, mostly upwards of 1 cm. long 



4. Stadmannii. 



