NAJADACEAE (PONDWEED FAMILY) 



14. 



15. 



16. 



a. Leaves all submersed and similar j. 



^.Leaves lanceolate, oblong or broader k. 

 k. Le^aves sessile or short-petioled, not clasping- I 

 i. Leaves finely and sharply serrulate ' 



m. Mature spike 3.8-5.5 cm. long 

 P>uit distinctly 3-keeled . 



Fruit with rounded, scarcely keeled side's ',','' 

 m. Mature spike shorter n. '^'='> • . . . 



«. Spike more than 1 cm. long. 



Foliage and spikes strongly suffused with red ; 3 or 4 car- 

 pels of each flower usually ripening 

 n. 8pS;"t^7 mm. t^'\^^''-'^^ 5 ^ (-rely 2) ckrpei; np;ning 



*. Leaves clasping or half-cTasping o 



o. Leaves half-clasping, elongate, with rounded cucullate tins- 



stipules conspicuous and persistent ; fruit sharply keeled ' 



o. Leaves cordate-clasping, if elongate with taperin- plaSe tins • 



stipules inconspicuous or soon reduced^ to shfeds- fruit 



rounded on the back or obtusely keeled n ' 



p. I^^^^3-4°,d^l^te or crisped, with 3-7 pron/iuent. nerves; fruit 



^"^aUeni^L""^' ^^''''^' Persisting as shreds; leaves lance- 



'"'^^obfong-ltnceSar^P^'"^'^^' '''''''' ^^"^ -^orbicula; 

 p. Leavesflat, scarcely crisped, with 1 'prominent nerve; 'fruit 



S^nfpirous^^^^ '. ''''.'''''' -^«- ^-^^«p«^' «^-tri 



^. Leaves linear to setaceous q. 



»-. Leaves free from the stipules, or, if slightly adnata to them 

 bearmg globose subsessile or short-sfalk^d spfkes in S 



Peduncles equaling or exceeding the spikes . 



I eduncles shorter than the spikes • • . 



''■ bVncTes^k'^'^'' '''"""^"^ ^' '^"™"'^^ *^« upper'most 



t. Principal leaves more than 1 mm. broad u. 

 u. l^eaves with very many fine nerves. 



bpikes many-flowered, in fruit 1.5-3 cm. long 

 Spikes 4-8-flowered, in fruit 5-8 mm. lono- " 

 u. Leaves with 3-T nerves v. " 



V. Mature fruit 8.5-4.5 mm. long. 



Stipules 0.5-1 cm. long; leaves acute; spikes canitifp 



Stipules 1.2-2 cm. long; leaves obtus? mucSte • 



., ^T . ^PJ^e^ subcylindric-ovoid . . ' "'^^"^^^^ ' ^^ 



'V. Mature fruit 2-3 mm. long w. ... .... 



w. Bases of the leaves bearing translucent glands; fruit 

 plump, obscurely or bluntly keeled ' 



Leaves 5-7-nerved ; stipules 1-2 cm. long oq 



Leaves 3-nerved ; stipules less than 1 cm Ion- ' ot 



' keef orTrfst^''"'^'" ' '™^' ^^"^^^^' ^^""^ t^-' 



^. Principal leaves less than'l mm. br'oad x ' ^^^^ ^-foliosuB 



X. FJant bearing winter-buds formed by the hardened ends of 



stTpu'esV'"'"^^ '""^""'"^ ^^ imbricated Sves and 



^' ^^Scili. ^°™^ Vr^m^vWy on very short axillary 



Leaves of the winter-buds widely divaricate 

 y W\nfIrVl *K^ winter-buds loosefy ascending . 

 y. Wuiter-buds borne at the tips of elongate branches 



Lear, S"^'^'-''"'"!' ''''^ ""'^y fi"e slender Ups, 

 Leaves flat or revolute. acute or short-acuminate 

 Leaves rigid, revolute ; winter-buds l--z cm lonjr 24 

 Leaves soft ; winter-buds about 1 cm. Ion- * 25* 



18. 



71 



p. alpimiH. 



P. heterophylluH. 



P- poly(jonifolim. 



P. crispuH. 



13. 



P. angustifoliua. 

 P. lucens. 



P. alpi7ius. 



P. hetero/>hi/llu8. 



P. mysiicii.s. 



P. praelong^cs. 



21. 



P. Richardsonii. 

 P. perfoliatus. 



P. hripleuroidea. 



P. epihydrus. 



P. hybridus. 

 P. dimorphus. 



P. zosterifoliuf,. 

 P. acutifolius. 



P. milii. 



P. obtusifolius^ 



P. Friesii. 

 P. pusillus. 



, V. magarensis. 



P. lateralis. 

 P. Vaseyi. 



P. gemmiparus. 



P. strictifoHus, 

 P. pusillm. 



