Soon to be described to science by aroid botanist Dr. Thomas B. Croat Ph.D., P.A. Schulze Curator of Botany at the Missouri Botanical Garden in St. Louis, MO, Philodendron plowmanii will be named in honor of the late botanist Timothy Charles Plowman (1944-1989).  There is an excellent book about Dr. Plowman anyone interested in his work should read titled One River by author Wade Davis.  My friend and aroid expert Leland Miyano from Hawaii offered these comments regarding Dr. Plowman and the text, "I would like to to promote the life and times of Timothy Plowman.  I grow several plants named for, or collected by Dr. Plowman and I am sure many others out there do also.  I think it should be mandatory reading for enthusiasts of Amazonian plants to read ONE RIVER by Dr. Wade Davis. It is an epic narrative whose primary protagonists are the ethnobotanists, Richard Evans Schultes and Timothy Plowman.  If the readers are willing to put up with high adventure and discovery....after approximately 500 pages of text, one will get a better appreciation of the dedication and sacrifice of these rare individuals. It will enlighten the reader to the importance of species and the true lack of knowledge that we currently possess about so many things. You will receive treasure in return."  Ethnobotany is the study of the highly complex interactions between people and plants.

Sometimes confused with Philodendron mamei, Philodendron plowmanii is a beautiful ovoid (oval) Philodendron from Ecuador and Peru, Philodendron plowmanii (plow-MAN-e-eye) is a terrestrial aroid with a stem that is known in botany to be repent.  The stem is not the support for any single leaf as is often thought by collector/growers but instead is the base of the plant.  The simple definition of "repent" is form of growth were the stem creeps across the ground rather than climbing a tree. Along the stem can be found internodes which are the segments found between two nodes.  The petioles which support the leaf blades as well as the roots grow from these nodes.  In the case of Philodendron plowmanii the internodes are short leaving the nodes closely spaced together.  (see photo near the bottom of this page)

Philodendron plowmanii is known by collectors to possess an unusual petiole.  The petiole is the stalk that connects  the lamina of a leaf blade to the stem at the plant's base.  The petioles possess an ornate ruffled edge which is both undulated (waved)  and sharply "D" shaped when cut as a cross section.  The petioles are broadly convex (curved outward) on the adaxial (upper) surface and are both undulated (wavy) and winged,  They are medium green in color while being  only slightly glossy and slightly streaked abaxially (on the upper surface),   The petioles are also undulated near the apex or upper end nearest the leaf blade and are often tinged with a reddish purple as can be seen in several of our photos.

Based upon Dr. Croat's published field notes the leaf blades of Philodendron plowmanii are subcoriaceous which indicates they are somewhat thin and less than leathery to the touch.  The blades are only slightly glossy to semi-glossy in appearance on the adaxial (upper) surface.  A leaf's upper surface is slightly bicolorous possessing two colors.  The blades are medium green and only slightly glossy as well as variegated with a paler yellow green as well as gray green on the blades' abaxial side (underside).  A blade's underside is semi-glossy.  If the lateral leaf veins are examined they can be observed to be deeply quilted (sunken) on the adaxial or upper surface while they are raised on the blade's underside (see photo, right).  The largest blades of our specimen exceed 30 cm (12 inches) in overall length.  

The cataphylls of Philodendron plowmanii are reddish and sharply double ribbed.  A cataphyll is a bract-like modified leaf that surrounds any newly developing leaf and whose purpose is to protect the emerging leaves as they form.  A double ribbed cataphyll is known as being a prophyll which is simply a specially modified cataphyll with two "keels" running along the upper surface.    A cataphyll is any foliar organ that has no differentiation between the petiole and blade.  The cataphylls persist at the base of the petiole as loose brownish fragments.

All Philodendron species are aroids.  An aroid is a plant that reproduces by growing an inflorescence known to science as a spathe and spadix.  The spadix is a spike on a thickened fleshy axis which can produce tiny flowers.  Some believe the spathe is a "flower" which is incorrect. The spathe is simply another modified leaf appearing to be a hood.  When an aroid is referred to as "flowering" the reference is to the very small flowers found on the spadix and has nothing to do with the spathe.  Within the inflorescence there are extremely small flowers found on the spadix at the center of the inflorescence during anthesis (sexual reproduction).   When ready to reproduce, the spadix of a Philodendron produces male, female and sterile flowers which are cleverly divided my nature into separate zones in order to prevent self pollination.  The female flowers are hidden inside a zone at the bottom of the spathe known as the "floral chamber" while the male flowers are exposed on the visible portion of the spadix.  If the female flowers are pollinated with pollen brought by an appropriate beetle from the genus Cyclocephala from another plant of the same species which is at male anthesis they will produce berries containing seeds.  For more information how Philodendron and other aroids reproduce click this link  Aroid Pollination

Philodendron plowmanii typically produces three inflorescences per axil.  Although variable in color the peduncle which supports the inflorescence is typically green and tinged red with whitish lines but may be heavily tinged pink to deep burgundy nearer the base.  The spathe tube of Philodendron plowmanii can be pale yellow green tinged red or dark violet purple on the outside and is white to slightly purplish violet to pinkish on the inside.  A peduncle is the internode between the spathe and the last foliage leaf.  Be aware that since the species is variable not every inflorescence will always produce the exact same coloration.  Philodendron species are known to be highly variable and not every leaf of every specimen will always appear exactly the same.  This link explains natural variation and morphogenesis within aroids and other species. Natural variation here. 

The specimen in our photos is fully grown as well as wild collected.  It was acquired as a grown cutting taken in 2007 by the staff of the Missouri Botanical Garden in St. Louis, MO and was originally collected on a trip with Dr. Croat by noted aroid collector Lynn Hannon (now deceased) as collection number 96-008 in 1996 in Morona-Santiago province in southeastern Ecuador.  The parent specimen is still in the Missouri Botanical Garden collection.  The best collection coordinates available are 02°46'30" S 078°14'W.   Lynn was renowned as a self taught taxonomist and frequently went on collecting trips searching for new aroid species with Dr. Croat in South and Central America. She donated much of her collection to the Missouri Botanical Garden upon her death.

The botanical information in this synopsis was extracted from the published works of aroid botanist Dr. Tom Croat.