76 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



[vol. 10 



Key to the Series of Section 1, Vouapa 



1. Leaflets 2-45-jugate or, if unijugate, with distinct petiolules. (Series 1.) 2. 



1. Leaflets unijugate or unifoliolate (some leaves with the leaflets bijugate in M. 

 palustre and very rarely in M. punctatum) . (Series 2.) 5. 



2. Leaflets with distinct petiolules 2.5-6 mm long. Bracts 5.5-17 mm long. Series la. 



2. Leaflets sessile. Bracts smaller. 3. 



3. Leaflets 2-6- jugate. Series lb. 



3. Leaflets 6-45-jugate. 4. 



4. Leaflets (4-) 6-10-jugate. Series lc. 



4. Leaflets 10-45-jugate. Series Id. 



5. Leaflets with a well-developed intramarginal nerve. Series 2a. 



5. Leaflets without a well-developed intramarginal nerve. 6. 



6. Ovary pubescent throughout or only marginally. Leaves always more than uni- 

 foliolate. 7. 



6. Ovary glabrous or the leaves unifoliolate. 8. 



7. Ovary pubescent on all surfaces. Series 2b. 



7. Ovary pubescent only marginally. Series 2c. 



8. Sepals five, free or the adaxial pair more or less united. Series 2d. 

 8. Sepals four, free. Series 2e. 



Key to the Series of Section 2, Stenasolen 



1. Leaflets 2-30- jugate. Series 3. 



1. Leaflets unijugate. Series 4. 



Key to the Species of Series la 



1. Leaflets all or mostly 2-3-jugate. 2. 



1. Leaflets all unijugate. 3. 



2. Sepals five; bracts not over 12.5 mm long and 4 mm wide. Leaflets not conspicuously 

 venose, the costa impressed on the upper surface. 21. M. campestre & vars. 



2. Sepals four; bracts 14-17 mm long, 4-7 mm wide. Leaflets conspicuously venose, 



the costa and venules more or less salient. 21'. M. xpectabile. 



3. Leaflets not at all arcuate, basally equilateral. Bracteoles not fleshy or crassate. 



22. M. arenarium. 



3. Leaflets more or less arcuate, moderately to conspicuously inequilateral at the base. 

 Bracteoles thick, fleshy. 4. 



4. Leaflets rounded-obtuse apically, oblong, obovate-oblong, or broadly elliptic. 5. 



4. Leaflets acute apically, elliptic to lanceolate-elliptic. 7. 



5. Plants pubescent in some parts; leaflets 2-2.5 times as long as wide. Bracteoles 

 about 10 mm long; petal 13-15 mm long. (23. H. canaliculatum) 6. 



5. Plants glabrous on vegetative parts and on most flower parts; leaflets less than twice 



as long as wide. Bracteoles 7 mm long; petal about 6.5 mm long. 23'. M. acrothamnos. 



0. Inflorescence axis strigulose. Leaflets with petiolules to 1 mm long, punctate. 



23a. M. canaliculatum var. strigulosum. 



6. Inflorescence axis very minutely puberulous. Leaflets with petiolules 3-10 mm long, 



not punctate. 23b. M. canaliculatum var. canaliculatum. 



7. Costa of the leaflets strongly salient on their upper surface. Bracteoles 3.5-8 mm 

 long; sepals 4-7.5 mm long; claw of the petal 4-5.5 mm long. 24. M. punctatum. 



7. Costa of the leaflets strongly impressed on their upper surface. Bracteoles 12-14 mm 



long; sepals 10-11 mm long; claw of the petal ca. 10 mm long. 24'. If. rubrum. 



Key to the Species of Series lb 



1. Peduncles 10-55 mm long. , , 2. 



1. Peduncles not more than 6 mm long. 3. 



2. Leaflets pilosulose-velutinous on the upper surface, pilose beneath. Inflorescence 

 pilosulose. 13. M. molle. 



2. Leaflets glabrous or sparsely puberulous basally on the lower surface. Inflorescence 

 glabrous or minutely puberulous. 16. M. multijugum & vars. 



3. Ovary densely to sparsely pubescent, marginally or on all surfaces. 4. 

 3. Ovary glabrous. 8. 



