Mamura s.l. SourceRutish.; Japan, Kyushucrustose green root, firmly attached to rock, resembling foliose lichen. (D and E) Griffithella hookeriana (Tul.) Cusset SourceRutish. Huber; India, PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/4398781 Keralabroad and narrow ribbonlike roots, attached to rock, an example of intraspecific variation.A S S SBCS S D ES XSFRFIG Basal members of tristichoid riverweeds. (A) Tristicha trifaria (Bory ex Willd.) Spreng. Novelo Philbrick s.n. March Mexico, Jalisco. (A) Floral shoot with terminal flower (arrow) and 3 photosynthetic shootlets (S), referred to as `ramuli’, with scalelike leaves along three rows. (B) Tip area of mm long vegetative shoot with 4 ramuli (S). Note more scalelike leaves inserted along stem (X). (C) Upper portion of totally grown ramulus (total length cm). (D) Lateral view of meristematic ramulus tip (slightly curved). (E) Ribbonlike root with capless tip, observed from below. Note presence of adhesive hairs (`root hairs’) on lower surface. (F) Terniopsis malayana (Dransfield Whitmore) M.Kato Dransfield KEWMalaysia, MalayaCreeping root (R), noticed from above, with young ramulus, showing scalelike leaves in 3 rows. Scale bars mm in a, B, C ; mm in D.3 carpels (capsule valves) within the Tristichoideae and two carpels in Podostemoideae and Weddellinoideae. The Podostemoideae have their flowers enclosed by a sacklike or tubular cover (`spathella’) which is lacking in Weddellina, the only genus in Weddellinoideae (Cook and Rutishauser, ; Koi and Kato, ; Kato,). Molecular phylogenies strongly enhanced our know-how from the evolutionary and biogeographical history of riverweeds, major to several taxonomic adjustments andproposals for regrouping (Kita and Kato, ; Moline et al ; Thiv et al ; Ruhfel et al ; Tippery et al ; Koi et al ; Khanduri et al). Promising studies published in the Japanese schools of Imaichi and Kato enable deeper insights in to the developmental genetics of numerous Podostemaceae. Since the two key subfamilies, Tristichoideae and Podostemoideae, are morphologically divergent, we are going to present them in separate sections beneath.Rutishauser Evolution of unusual morphologies in Lentibulariaceae and PodostemaceaeA C C M B C FR RP D E HFIG Tristichoid riverweed Indotristicha ramosissima (Wight) van Royen Rutish. Huber India, 
Kerala. (A) Seedling with two cotyledons (C) and shortlived plumule, adventitious root (R) as exogenous outgrowth of hypocotyl. Note adhesive hairs replacing radicle. (B) Flower in anthesis, perianth (P) overtopped by three stamens and stigma (arrow). (C) Tip of almost mature ramulus (total length mm), showing scalelike leaves in helical arrangement. (D) Portion of creeping, ribbonlike root (R), noticed from above. Note endogenous origin of disklike holdfast (H), fixing the shoot bud (black arrow) for the rock. (E) Transversal section of growing ramulus tip. Note spiral arrangement of broad scalelike leaves, consisting of a single cell layer each. (F) Meristematic tip of young ramulus providing rise to ligulate leaves (asterisks). A-804598 Apical meristem (M) conical and slightly curved. Scale bars mm in B, C, E; mm in a, D; mm in F.ABC D E FT AFIG Tristichoid riverweed Dalzellia zeylanica (Gardner) Wight Rutish. Huber India, Kerala. (A) Crustose creeping shoot (resembling foliose lichen) in vegetative stage, as seen from above; scalelike leaves inserted on upper surface and along margin. (B) Mature stage of crustose creeping shoot, as noticed from above; most scalelike leaves dropped. Note reproductive brief shoot with flor.Mamura s.l. SourceRutish.; Japan, Kyushucrustose green root, firmly attached to rock, resembling foliose lichen. (D and E) Griffithella hookeriana (Tul.) Cusset SourceRutish. Huber; India, PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/4398781 Keralabroad and narrow ribbonlike roots, attached to rock, an instance of intraspecific variation.A S S SBCS S D ES XSFRFIG Basal members of tristichoid riverweeds. (A) Tristicha trifaria (Bory ex Willd.) Spreng. Novelo Philbrick s.n. March Mexico, Jalisco. (A) Floral shoot with terminal flower (arrow) and three photosynthetic shootlets (S), referred to as `ramuli’, with scalelike leaves along 3 rows. (B) Tip area of mm extended vegetative shoot with four ramuli (S). Note further scalelike leaves inserted along stem (X). (C) Upper portion of completely grown ramulus (total length cm). (D) Lateral view of meristematic ramulus tip (slightly curved). (E) Ribbonlike root with capless tip, observed from under. Note presence of adhesive hairs (`root hairs’) on reduce surface. (F) Terniopsis malayana (Dransfield Whitmore) M.Kato Dransfield KEWMalaysia, MalayaCreeping root (R), seen from above, with young ramulus, CBR-5884 biological activity displaying scalelike leaves in 3 rows. Scale bars mm inside a, B, C ; mm in D.3 carpels (capsule valves) in the Tristichoideae and two carpels in Podostemoideae and Weddellinoideae. The Podostemoideae have their flowers enclosed by a sacklike or tubular cover (`spathella’) that is lacking in Weddellina, the only genus in Weddellinoideae (Cook and Rutishauser, ; Koi and Kato, ; Kato,). Molecular phylogenies strongly enhanced our information in the evolutionary and biogeographical history of 
riverweeds, top to several taxonomic adjustments andproposals for regrouping (Kita and Kato, ; Moline et al ; Thiv et al ; Ruhfel et al ; Tippery et al ; Koi et al ; Khanduri et al). Promising studies published from the Japanese schools of Imaichi and Kato enable deeper insights in to the developmental genetics of different Podostemaceae. Because the two major subfamilies, Tristichoideae and Podostemoideae, are morphologically divergent, we’ll present them in separate sections beneath.Rutishauser Evolution of unusual morphologies in Lentibulariaceae and PodostemaceaeA C C M B C FR RP D E HFIG Tristichoid riverweed Indotristicha ramosissima (Wight) van Royen Rutish. Huber India, Kerala. (A) Seedling with two cotyledons (C) and shortlived plumule, adventitious root (R) as exogenous outgrowth of hypocotyl. Note adhesive hairs replacing radicle. (B) Flower in anthesis, perianth (P) overtopped by 3 stamens and stigma (arrow). (C) Tip of almost mature ramulus (total length mm), displaying scalelike leaves in helical arrangement. (D) Portion of creeping, ribbonlike root (R), observed from above. Note endogenous origin of disklike holdfast (H), fixing the shoot bud (black arrow) towards the rock. (E) Transversal section of expanding ramulus tip. Note spiral arrangement of broad scalelike leaves, consisting of a single cell layer every single. (F) Meristematic tip of young ramulus providing rise to ligulate leaves (asterisks). Apical meristem (M) conical and slightly curved. Scale bars mm in B, C, E; mm inside a, D; mm in F.ABC D E FT AFIG Tristichoid riverweed Dalzellia zeylanica (Gardner) Wight Rutish. Huber India, Kerala. (A) Crustose creeping shoot (resembling foliose lichen) in vegetative stage, as observed from above; scalelike leaves inserted on upper surface and along margin. (B) Mature stage of crustose creeping shoot, as observed from above; most scalelike leaves dropped. Note reproductive brief shoot with flor.
